Longhorn Cowfish ~ Long-horned Cowfish

Family: Ostraciidae Picture of a Cowfish, Lactoria cornutaLactoria cornutaPhoto © Animal-World: Courtesy David Brough
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I kept one of these amazing guys for a long time, he was almost a foot long when he died. As far as when he did die he did not release a toxin and was surprised to... (more)  Jessica Reyes

   Probably the most well known of the boxfish! The Cowfish, Longhorn Cowfish, or Long-horned Cowfish can be seen in almost every public aquarium. They are hardy and they love to eat!

   The Cowfish, Longhorn Cowfish, or Long-horned Cowfish are easily recognized by the horns on the forehead and the bottom rear of the body. These horns make them hard for predators to swallow. In any case their flesh is poisonous and would not make for a very good meal!

  NOTE: The Cowfishes in the genus Lactoria, especially this Cowfish, Longhorn Cowfish, or Long-horned Cowfish must be dealt with carefully. If overly harrassed or stressed, it can release the toxic substance, ostracitoxin. This is a response to stress and can poison your tank. Make sure you keep this fish in a comfortable and not overly stressed environment, and keep it well fed!

For more Information on keeping this fish see:
Guide to a Happy, Healthy Marine Aquarium

Geographic Distribution
Lactoria cornuta
Data provided by
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Tetraodontiformes
  • Family: Ostraciidae
  • Genus: Lactoria
  • Species: cornuta
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Maintenance difficulty:    The Cowfish, Longhorn Cowfish, or Long-horned Cowfish is easy to keep. Boxfish are not challenging if you feed young specimens several times a day. Start with brine shrimp.
  The puffer's teeth will continually grow throughout its life so you will need to supplement their diet with some hard shelled foods. Occasionally offering foods such as live ghost shrimp and various live snails will keep their teeth worn down.

Maintenance:    Feed all kinds of live and frozen foods. The boxfish also eats greenstuffs. Best to feed small amounts several times a day. We generally feed squid, shrimp (the same kind people eat), mussels, and all kinds of chopped up fish. Be sure to wash these foods thoroughly before feeding. A good vegetable formula like Formula II is also beneficial. Live fish will also be taken but should not be fed exclusively.

Habitat: Natural geographic location:    Cowfish, Longhorn Cowfish, or Long-horned Cowfish are found in the Indo-Pacific: Red Sea and East Africa to the Marquesan and Tuamoto islands, north to southern Japan, south to Lord Howe Island. Inhabits inshore on coastal muddy or sandy habitats in still bays, and commonly found in harbours and estuaries. Small juveniles on protected shallow mudflats. Found in weedy areas near rocks or reefs. Juveniles often near river mouths and in brackish water. Adults are solitary, juveniles often form small groups. Large adults are shy. Feeds on benthic invertebrates by blowing away the sand

Foods:    All kinds of meaty foods and greenstuffs. A bottom feeder. Puffers are primarily predatory fish in the wild though they do graze on a bit of algae. This puffer will enjoy all kinds of meaty foods including shrimp, worms, clams, various mussels, snails, tunicates, and fish.They are not picky eaters and will quickly become adapted to a variety of prepared aquarium foods and an occasional algae wafer. Flake food is not recommended. Even though they may eat it, puffers will not thrive on it.

Social Behaviors:    Apparently this fish is sometimes aggressive and sometimes not. Keep an eye on newcomers with an established boxfish and any new boxfish that are added to the aquarium.

Sex: Sexual differences:    Apparently many boxfish are easy to sex but we haven't found this information yet.

Light: Recommended light levels:    No special requirements.

Temperature:    No special requirements. Normal temperatures for marine fish is between 74 and 79 degrees Fahrenheit.

Length/Diameter of fish:    Cowfish, Longhorn Cowfish, or Long-horned Cowfish adults can grow to 50.0 cm (20 inches). They usually only get about 40.0 cm (16 inches) in aquariums. Their size can be deceiving since they are usually very small at the pet stores.

Minimum Tank Length/Size:    A minimum 100 gallon aquarium is recommended.

Water Movement: Weak, Moderate, Strong    No special requirements.

Water Region: Top, Middle, Bottom    No special requirements.

Availability:    This fish is available from time to time.

Lastest Animal Stories on Cowfish

Jessica Reyes - 2012-06-08
I kept one of these amazing guys for a long time, he was almost a foot long when he died. As far as when he did die he did not release a toxin and was surprised to find out that they release the toxin when they die stressfully. As sad as I was when he did die it made me feel better knowing he was happy and probably died of old age.

  • Dustin - 2013-03-02
    I just bought a cowfish today. They are amazing creatures and very unique. I'm sorry for your loss. My cowfish Billy is so full of life.
Jaimie - 2009-10-04
Hi everyone, had a cowfish about 2 years now. Was less than an inch when I got him, now just over eight. Eats like a horse. Predictably my six year old daughter named him moo..... Anyway, he eats from my hands, let's me pet him, follows me round the room, great! On the negative side, squirts me if I dont feed him and squirts while I'm out, leaving streaks on the tank and puddles on the floor. Worst of all, on at least 3 occasions when cleaning, dropped my gaurd and he decided I was food! In less than a second has managed to shred enough skin off my wrist, finger, and arm to draw blood. Shouldn't bite the hand that feeds you! Try telling him that...

tennille - 2003-11-04
I have a long horned cow named pickle, but am worried because I have been told that if he dies my whole tank will die too as he is poisenous. But so far so good, and you guys say he is easy to keep. He is really friendly, and a very interesting fish.

Josh - 2005-12-16
I have a longhorn cowfish named SPIKE. I have to sat that he/she is by far most simple fish to care for that I have ever had. He often begs for food and as we found out the other day gets very depressed when he can not see people. We have a blackout curtian on the tank due to to many windows in my place. we left it on a bit too long, and after taking it off Spike was dark in color and very reclusive. Also I think that it takes alot for them to release any toxin. Spike when we first got him got stuck in an intake and wound up breaking off one of his horns(it has since grown back) with no toxin release. Also he has chased a piece of food up the refugium intake and got his mouth stuck. He was stuck for atleast an hour before I noticed him (I have spike proofed the tank since then). He came out with a big hikky but again no toxin. We have also moved the tank and him without any toxin release. Needless to say I think that toxin release is very rare and most average aquarium stress will not be enough to provoke release.

Gigi - 2009-11-23
I dont have a cowfish. I want one though. Any advise? Do they need a salt water tank or a freshwater tank? I need 2 know so I can c if I can get one. PLZ RESOND!

  • Scott - 2010-02-25
    Cow fish require a salt water marine tank! I'd suggest reading about salt water marine before making the commitment. Cheers
  • Jenna - 2010-08-31
    Hey Gigi, they are a lot of fun. They need saltwater and lots of it. When getting a tank you need to realize that rule of thumb is 1 fish per 10 gallons. So if you get 30 gallon you can put 3 fish in it. But also think about rocks they take up space too. So good luck hopefully you will enjoy your cow fish.
  • Anonymous - 2010-09-01
  • Krista - 2011-09-14
    The rule of thumb 1 fish per 10 gallons is _wrong_. The best way to plan a fish tank is to have about 5 gallons per every adult inch of fish. So because the cowfish can get up to 20 inches you'd want at least 100 gallons just for that one fish. If you add any more fish, any rocks, sand or plants that take up room you need _more_ gallons.
  • Alex Burleson - 2012-02-11
    Cowfish, are Salt Water fish. Additionally, they require a very experienced fish keeper to keep them. You may find reading this article about Cowfish useful.
Kuba - 2011-05-31
If I buy cow fish as a baby can i keep him in 28 gal nano cube?
How long i can have him for ?
I heard they grow up slowly.

  • Charlie Roche - 2011-05-31
    28 gallons is big enough as the cow fish will supposedly be 20 inches as an adult. Figure one inch of fish (as an adult) for each gallong of water. 20 inches so at least 20 gallons as you have to subtract for plants and flooring and decorations. Leave your question up and I would look into this a little more cuz some say problems with these nano cubes.
  • Krista - 2011-09-14
    No. 28 gallons is not big enough. The Longhorn Cowfish needs at least 100-150 gallons at full length. Even as a baby 28 gallons won't be big enough and he will probably die and poison everything else in your tank.

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