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.
Pink Skunk Clownfish, a pink anemonefish with a white skunk stripe!
Beginners to advanced aquarists love this little dude. The Pink Skunk Clown is one of the most unique anemonefish. It stands out with its awesome pink hue topped with a skunk-like white stripe. But even better, it is one of the smallest clownfish with a personality to kill for. It works well in a reef tank, but is just as wonderful in a community setting.
It is a delicate clownfish with a shy and reclusive nature, happiest when it can call an anemone its home. Along with its color and friendly personality, its timid characteristics also add to its charm. For the aquarist who is willing to make sure the tank is pristine, this unusually decorated clownfish can provide a one-of-a-kind attraction for years. Beginners and advanced aquarists alike can marvel at its beauty and pleasant personality.
Keep it with other small fish that are peaceful and relatively calm and you can enjoy a lifetime of beauty and perfection in a smaller aquarium. Or conversely, add it to a reef with an anemone and have a supreme addition with interesting color and personality.
It can be kept singly without an anemone, but is also great as a pair with an anemone and a small group of like kind sub adult companions. Its diminutive size makes it great for a smaller aquarium, and beginners can have great success as long as they use due diligence in keeping the water in top condition.
Pink Anemonefish can be obtained as captive bred fish and are available as a single specimen or as a pair. Keep one in a smaller tank, or a pair and some little guys in a larger tank and you’ll have a great aquarium.
Check out more about this pink “skunk-striped” anemonefish. Pictures and information for Pink Skunk Clownfish, along with habitat and aquarium care!
Clarice Brough 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.
If you are fascinated by saltwater fish… This is going to be fun and exciting.
Under the Sea Radio Show…. Join us!
Blog/Talk radio show featuring Clarice Brough from Animal-World. Learn about hardy saltwater fish for the beginning marine aquarist. The discussion will be centered around an aquarium the size of 30 gallons, and the hardy fish that are available for beginning saltwater aquarists. Included will be Damselfish, Clownfish, Cardinals and many others.
Keeping marine fish is a wonderful hobby. If you are a beginner about to start your first saltwater aquarium, you are embarking on a grand adventure. Marine fish are some of the most spectacular aquatic animals, and there is a very diverse and magnificent selection to choose from. The benefits of keeping saltwater fish are many. They are entertaining, relaxing, and make an incredibly beautiful show piece for your home.
Saltwater fish keeping is an exciting hobby for anyone interested in learning more about life in our oceans. You can see pictures and information for all sorts of marine species in our World of Saltwater Aquariums atlas too.