Crabs in the Saltwater Aquarium
No, I am not talking about our old aunts or other relatives, although they can probably fit loosely into this topic if I could throw them in my saltwater tank! For the sake of family peace, however, I have had to refrain myself during one visit. An odd circumstance arose that would have lent itself to the submergence of a crabby relative INTO my 150 gallon tank! Yet, I digress…
I am talking about crabs; all species, all genus, all colors, all shapes and all sizes. Be assured, that eventually these little hellion monsters, with evil intentions and back biting ways, will murder another creature in your tank, that you spent your hard earned money on! It’s just their nature, and they can’t be blamed. Even the ones with “small claws” have been known to cause problems, especially in a reef tank. I am sure there are a few well behaved crabs out there, but I am not risking my inhabitants on something that can be easily replaced with a less opportunistic murderer.
My first experience with the “little darlings,” was when I bought my first “clean up crew” for my 8 week old cycled 55 gallon saltwater tank. During this time, my research was quite focused on water quality, live rock, substrate, skimmers, heaters, and lighting. I did however, intend on doing research on the fish I was going to buy. After all, how can you screw up buying a “clean up crew?” …Everybody else is doing it!
My appreciation for hermit crabs were short lived. Over a period of about 4 months, the hermits, one by one, took out my snails, which of course COST more then THEY did. Yes, there was plenty of food and algae for both, perfect water parameters, and no predatory fish; so nothing else would have killed the snails. For me, the last straw was the loss of my prized Jumbo Nassarius Snail, who was one of five I had in my tank. The day I saw a hermit crab rockin’ that snail’s shell, was the day I pulled each and every one OUT of the tank and returned them to the store.
I actually have witnessed larger hermit crabs starting to attack a resting or sick fish! Then a friend of mine related a story of a puffer fish that was attacked at night, and dead by morning. She owned the puffer for a long time, and it was not sick. I remember once, when looking in someone else’s reef, I noticed a hermit crab sitting on top of a healthy SPS coral. As I observed this little beast, I noticed it was tearing the flesh off of the coral! Enough said!
If a fish dies, your nassarius snails will converge and consume, but they will never touch a live fish, only a rotting one. This will keep your water quality from deteriorating if a fish does die. This makes nassarius snails great inhabitants! Over time, I discovered that brittle starfish also do just as good of a job getting extra food that the fish missed.
Back to the crabs! Well, against my better judgment I did buy an emerald crab down the line to take care of some green bubble algae. Once again, another little monster crab had to be extracted as it threatened my Halichoeres wrasses that were napping under the sand. I swear you could hear him say, “Where did those morsels go? The algae just ain’t cutting it!” My wrasses were unusually afraid of this emerald crab as it grew. So were we…
The worst experience I’d ever had was a reef crab that hitchhiked on some live rock. I bought the rock from a gentleman whose system crashed when the power went out. This is common during hot summer days in Las Vegas. I didn’t know there was a little monster stowed away in the rock and the way I found out was not cool! One morning, my fairy wrasses came up to be fed, and I noticed that my Scott’s Fairy Wrasse was no where around. This was odd, because he was usually the first in line for breakfast. I started looking for him and found this big, black, butt ugly, reef crab slowly scraping the now gutted sides of my most expensive wrasse! The Scott’s was NOT sick and I owed him long enough to rule out disease. Why is it ALWAYS the MOST expensive fish that is killed?
Thus started my long search for this monster in the bowels of my tank after he scampered away…. sideways… the LITTLE FREAK! I found him in a twisted and gnarled piece of live rock, which of course was UNDER a bunch of other live rock! So I had no choice but to remove the rock from the tank and chase him out of the middle. That was the WEIRDEST 30 minutes of my life up to that point. With saltwater tanks, these weird minutes start to accumulate over the years… just wait, you’ll see! So I got the little turd out and put him in a refugium as I decided what his fate would be. Let’s not go there.
I started to search for fish that would not typically eat snails but WOULD eat crabs. Why? I had this suspicion he had a brother! Enter the Harlequin Tuskfish. I loved that fish! For as big and scary his teeth were, he was not even the dominant wrasse in my tank. One day, about a week after I bought him, I found remnants of yet ANOTHER reef crab on the substrate. So I blurted out, “WHO’S A GOOD BOY? WHO’S A GOOD BOY? WHOOOOOSE A GOOOOD BOY?!?!” Yes, another weird moment, as my family members looked at me perplexed; since, well, we DIDN’T have a dog!
Upon further research, the Internet supplied more and more horror stories of crabs wreaking havoc in tanks. Reef crabs include Mithrax Crabs (Mithraculus sp.) and Xanthid Crabs, and these are some of the worst culprits. The Mithraculus crabs belong to the Majidae family of “spider crabs”, which has around 200 species in 52 genera. The Xanthidae family is huge, with 133 genera and 572 known species.
A wide variety of marine crabs can be seen here, at Dr. Jungle’s Animal-Image: Saltwater Crabs
Now I am sure there are crab lovers out there, and in certain set ups, hey, go right ahead!
Yes, they are very useful, but only in the ocean. There are many seasoned writers and hobbyists who have written books that will back me up on not keeping crabs in most closed systems. One may say that there are certain crabs like the tiny blue-legged hermits that don’t cause problems. Well, except if you happen to have those little nassarius snails! So YES, I did try those and they started to kill my little nassarius snails that, by the way, were perfectly fine up to that point.
Crabs are opportunistic scavengers, not pets. They are “cute” but the snails in your tank are thinking, “Well, I know one day I will be disemboweled by that heathen.” So the snails sulk away, out of the grip of the new resident… for now.
Carrie McBirney is a team member at Animal-World and has contributed many articles and write-ups.
Good, bad, and best choices for the saltwater aquarium beginner.
As I sit here staring at my 75-gallon semi reef tank, with my Platinum and Picasso Percula Clownfish, Halichoeres Garnoti Wrasse, and Royal Gramma… yes, I’ve started over again after moving… I thought about how I got to this point. I thought that the things I’ve learned, a few good choices along with my newbie mistakes, which started in 2005, might be of use to someone. As I reflect, I realized it wasn’t all bad and I did learn a lot along the way.
My first saltwater tank was a 55-gallon in 2005. The first bit of advice I can give you is that you WILL want corals, so just buy a good light now! You can remove some of the bulbs if you think you are going to have a fish only tank, but you will have all the watts you need when you can’t help but buy that first coral!
Back to my first tank… I read what I could on the internet, and at the time, you could get live Fiji rock on eBay from a reputable dealer for $.99 a pound! Excited to find such a great buy, I did order the 50 lbs of live rock and eagerly awaited its arrival. The tank was set up with the proper salt level of 1.023, and this made sense to me since the ocean is about that or higher.
That was my first good choice. My first bad choice? Well that would be crushed coral. A guy at the LFS (live fish store) who seemed to be knowledgeable on the subject, we will call him Mr. Crushed Coral, told me that this was the best choice. I recall they were out of sand, yet he assured me this was better at keeping the pH up, and yes that made sense to me… at the time, and in certain applications it does have its uses.
One good choice was that a different guy at my LFS, who was actually quite knowledgeable in some areas, told me due to the hot summers here in Vegas, to wait and see what temperature my tank could maintain on its own. He said if 82°F was the lowest you could get it to in the summer, then keep it there! This was good advice due to the fact that keeping it at 78°F in the summer would be near impossible, and the fluctuations between 78°F at night and 82° during the day would cause Crypt and other stresses. I also found from this the best way to medicate your fish in the reef! Read on!
Crushed Coral, Crushed Heart
So I went home, rinsed and then dumped in my crushed coral per Mr. Crushed Coral’s instructions. I also observed where the temperature tended to hover and found that 82°F was the magic number, and set it there. In the meantime, the live rock had been delivered to my house, and it was amazing!
At the 4 week mark I did a 50% water change, as advised by Mr. Crushed Coral, and I saw emerge from the rock, a peanut worm! Coolest, freakiest thing I ever saw… well up to this point. The little dude kind of hung around the rock for the first week after that water change and then decided, “Hey, I need to burrow, because I am a WORM after all!” That did it. The crushed coral sliced and diced up Mr. Wormy in no time as I watched dumbfounded that I thought sand was not the better choice!
Upon further research on the internet, which we all tend to do after a mistake which we never even realized, I found it WAS a mistake. I found that good quality reef sand will also keep up your pH! So I bought this sand and replaced half of the crushed coral initially, then the other half 2 weeks later, to give the bacteria and other creatures a chance to migrate. I also read how crushed coral, especially when several inches deep can hold anaerobic pockets, which can cause issues if released. Lesson learned, note to self… only reef quality sand.
Starfish, Love/Hate Relationships
I was now ready for my clean up crew, which you guessed it, included hermit crabs, snails, and a sand-stirring starfish. Yeah, it was the Mr. Crushed Coral dude, again. Well, one out of 3 creatures in the cleanup crew were not too bad. Why do I say this? Well the hermits systematically hunted and killed all my snails for their shells, so yeah, THERE was money well spent! To this day, I will only add a hermit crab if I have a fish that likes to eat them! Yes I love Harlequin Tuskfish!
I also noticed over the next 12 months my tank seemed unstable. I was testing my saltwater tank daily, almost to an OCD level! Thus my parameters of calcium, magnesium, iodine, etc were all good, no ammonia or nitrites and only about 5 nitrates. I also slowly added fish, at the rate of one every 2 weeks. One day I noticed my sand-stirring starfish had crawled up on a rock, and later that same day, during a conversation with my seawater supplier, I was telling him how my tank just didn’t seem to want to stabilize.
He happened to look in the tank and see the starfish on the rock (at the time I didn’t know it was dead) and he said, “There is your problem! They eat all the good stuff in the sand, and then once it is gone, they starve to death! In a much larger tank they are fine, but not a 55 gallon.” I was like, “Oh great guru, please guide this newbie!” We took out the starfish, uh, okay Sea Star, and to this day I still have it… on my window sill… yeah, I know.
He then sold me some of his live rock from one of his established systems for $2.00 a pound and I got some GREAT stuff! He also gave me copepods, then after a few weeks, my tank was stable! To stir sand, I found the jumbo nassarius snails are best and their babies are adorable! At that point, my sand was being stirred, water was stable and I then had a new brittle starfish that was very cool, eating the extra food the others missed. I loved that starfish! Err, Sea Star. Note to self, don’t even bother with Linckia Starfish.
One bit of information I stumbled upon while talking to an online website who sold fish bears repeating. They told me they purposely keep their tanks at 82°F to prevent the Cryptocaryon life cycle from completing, thus their fish rarely if ever had it! This would explain why I never had Crypt, and why any fish that I added who may have had a few spots never developed any more. I will say to this DAY, when my tank is at 82°F NO ONE gets sick!
To illustrate how harmless 82°F is, around the early part of 2006, my local UPS guy asked if I had a saltwater tank, noting the companies I was ordering from. I showed him my 55-gallon tank and on the spot he offered me, for FREE, a 150-gallon tank! He just finished with the hobby. This was oddly a foreshadowing of what I WOULD BE DOING with tanks over the next decade, but didn’t know it yet! So I continued with the temperature staying at 82°F, and I added more live rock and inhabitants to my 150-gallon reef over time. Eventually I had a Heteractis Magnifica (Magnificent or Ritteri Anemone), 2 Bubble Tips, various SPS (soft polyped stony corals), mushrooms (corallimorphs) zoanthids, one Kenya Tree, and LPS (large polyped stony corals), with all inhabitants, including fish, thriving. Of course, I never had cold-water fish! Note to self… no, you cannot have the Catalina Goby.
One time, back in 2007, I ordered some black perculas… yeah they were HOT back then! One had Brook! Quinine Sulfate, pharmaceutical grade cured one as I treated it in a separate tank, but I lost the male. I bought it from Nationalfishfarm.com and these people are very knowledgeable! One morning I noticed, in my 150-gallon tank, a few of my fish had Crypt, and the temperature was only 77°F because of a failed heater. I had an extra one on hand, but I needed to figure out what to do.
After hours of researching, I settled on Seachem’s Metronidazole and Seachem’s Focus. The idea behind these products was awesome! The food and medication is bound together and will not affect the water chemistry or harm any inverts or bacteria! I used 3 parts Focus (binds the food and the other Seachem medication) to 1 part Metronidazole (used for Crypt and a few other illnesses) to 1 tablespoon of fish food, which can be dry or wet, then stored the leftover in the fridge. Upon following the instructions, my fish recovered very quickly! No need to bomb the tank, remove the fish, or relocate corals! To my horror, upon one of the feedings, my Magnificent Anemone accidentally ATE this mixture of food and medication, (thanks to the clownfish “feeding him”), but nothing ever happened! It is an amazing product! Note to self… check the expiration date on the Metro and Focus…
Next time I will talk about my “charge” mistakes. Fish, corals, or creatures I was talked into buying at the local fish store, and regretted it every day since… but learned a lot from!
Saltwater aquarium success can be yours! Learn how to set up your aquarium with our Saltwater Aquarium Guide, Beginner Saltwater Aquarium Setup and Care. Then select the best fish with our Beginner Saltwater Fish Guide, Hardy Marine Fish for the Beginner’s Saltwater Aquariums.
Carrie McBirney is a team member at Animal-World and has contributed many articles and write-ups.
A beautiful bright red coral species, described as Psammogorgia hookeri, has been found in the Peruvian region of the Eastern Pacific!
It was the brilliant reddish color of this soft coral that first caught the attention of Yuri Hooker in 2002, and he collect the first specimens at that time. Hooker came across it again in 2008 while he was researching marine sponges, and at that time he was able to collect new specimens.
Dr Yuri Hooker is a biologist and naturalist at the Cayetano Heredia Peruvian University in Lima, Peru. In an article published by El Comercio, A new species of coral inhabiting the waters of Paracas, he says that with the 2008 specimens he began to “start the scientific process of identification and description”. It was then validated as a new soft coral species in 2014 by Odalisca Breedy, a research specialist in Octocoral Taxonomy at the University of Costa Rica (CIMAR), and her associate Hector M. Guzman, a marine biologist with the Smithsonian Tropical Research Institute (STRI).
This new coral species has been named Psammogorgia hookeri in honor of Dr Yuri Hooker. Breedy and Guzman describe this honor in their report, A new species of alcyonacean octocoral from the Peruvian zoogeographic region, published by Journal of the Marine Biological Association of the United Kingdom 2014, as bestowed “in recognition of his (Hooker) indefatigable and valuable contribution to the knowledge of the marine invertebrates and natural history of Peru.”
Breedy and Guzman, both experts in soft coral taxonomy and ecology, identified this new species based on colony characteristics and examinations using both light and scanning-electron microscopy. This species is described as a member of the Alcyonacea order of soft corals in the Holaxonia suborder of gorgonians. It belongs to the Plexauridae family, which are soft corals that form branching colonies and are often known as sea rods or sea fans. Within this family it is placed in the genus Psammogorgia, which now contains 14 described species, with Psammogorgia hookeri being the newest member.
The discovery of this new soft coral has created quite a stir. The rich coral red coloring makes it an undeniable beauty, but it seems to have a very limited occurrence. It has only been found from Isla San Gallan, in the Paracas National Reserve. This reserve is located in Ica, Peru and contains the Paracas Peninsula, coastal areas, and extends inland into the tropical desert areas.
This vibrant coral is thought to possibly be endemic to the Paracas National Reserve. During his research, Hooker says he has traveled almost all of the Peruvian coasts, from Tumbes to Tacna, but has only found these soft corals in the Paracas region.
The waters of this region are cool in contrast to the more congenial waters of other eastern Pacific tropical regions, where temperatures can exceed 82.4° F (28° C). Breedy and Guzman say, “the diversity of Peruvian shallowwater octocorals may be low, but species and ecosystems have adapted to dramatic coastal oceanographic changes.” They suggest that both “seasonal and inter-annual upwellings” and El Nino impact the region, changing the surface temperatures of the water. That in turn creates a “turbid green-to-brown ecosystem”, and thus effects the bio-productivity.
Description and habitat
Breedy and Guzman describe Psammogorgia hookeri colonies as small, bushy, and branching. They are about 3″(8 cm) wide with branches that reach about 7 3/4″ (12 cm) in length. They are a bright coral red color with translucent polyps.
The scientists described the coral’s colony habitation as clusters on rocky ledges and cliffs, and then spreading along the substrate. They say that areas they inhabit are generally “surrounded by other organisms such as sponges, worms, sea urchins and brachiopods among other sessile creatures.” However this coral is not a shallow water species. It has not been found at depths of less than 65′ (20 m).
Interestingly, this soft coral has been seen attached to mussel shells in local fish markets! However its availability for the reef aquarium is pretty slim right now, as finding Psammogorgia hookeri specimens in fish stores or online is difficult, if not impossible.
Learn more about the types of soft corals categorized as Gorgonians at Types of Gorgonians, Sea Fans and Sea Whips on Animal-World, which also includes coral guides for different species with pictures, background information, and the aquarium care needed for keeping them in a mini reef.
Clarice Brough is a team member at Animal-World and has contributed many articles and write-ups.
Two Thumbs Up! To Planet Catfish and the PlanetXingu Project
Planet Catfish and founder Julian Dignall truly deserve our praise and recognition for their successful fundraising project, PlanetXingu. Julian conceived PlanetXingu almost a year ago to help research into the Rio Xingu in Brazil.
PlanetXingu has been a great success. Big kudos to these guys in the UK for stepping up to the plate. Hundreds of aquarists and fish lovers became engaged and donated both money and time to the project. They not only reached, but exceeded their $11,000 goal!
Julian will be hosting an exciting event this coming Sunday, Feb 9th, 2014, where you can meet two of the major players on the project, Mark Sabaj Perez and Nathan Lujan. There will be two online sessions , one at 1900 GMT and the other at 1900 EST. Sign in at: http://tinychat.com/planetcatfish
The project evolved due to the plight of the endemic and migratory species of the Xingu River in Brazil. The Brazilian Government is currently constructing the Belo Monte Dam on one of the Amazon’s major tributaries, the Xingu River. It is estimated by Amazon Watch in their article, Brazil’s Belo Monte Dam, Sacrificing the Amazon and its Peoples for Dirty Energy, that this will be the world’s third largest hydroelectric dam.
This project brought to light many concerns over the impacts this will have on communities, rivers, and forests throughout the Xingu basin. Amazon Watch says it is designed to divert 80% of the river’s flow, “devastating an area of over 1,500 square kilometers of Brazilian rainforest”.
Dignall envisioned bringing together a communty of fish lovers and scientist to the aid of Rio Xingu. His inspiration was to help assist both researchers in the field as well as those that keep and breed Xingu basin species in captivity. Thus the launch of the PlanetXingu fundraising project in March 2013. The aim of the project was to raise $11,000 by January 1, 2014 to purchase equipment for studying the river before, during, and after the dam’s construction. You can learn more about PlanetXingu on Planet Catfish’s An Introduction to the project.
We are proud of the efforts of Julian Dignall and Planet Catfish, not only on the PlanetXingu project, but for their years of online information. Their website originated in 1997/98, at about the same time as Animal-World. With well over 2400 catfish varieties, it is a great resource for pictures and taxonomical information on catfish species, and one of our premium references. In fact one of our super team members, Ken Childs, who has over 2 decades of fish experience in the wholesale arena, provided numerous catfish pictures to their database.
Learn about the history and background of catfish on Animal-World, along with aquarium guides for the different kinds of catfish: Catfish Varieties, Fish Guides for All Types of Catfish
Clarice Brough is a team member at Animal-World and has contributed many articles and write-ups.