Taken from
http://aqualandpetsplus.com/Oddball,%20Crocodile%20Fish.htm
Crocodile Fish Factoids
Origin: Lots of countries in the Indo-Pacific area plus Australia
Temperature: Tropical
Size: Six-inch maximum. Five more likely.
Changes colors to blend into surroundings. Always hides
Water: Prefers brackish. Adapts to marine and freshwater.
Foods: Decided predator
Habitat: Crazy fish live in marine, brackish, and freshwater. They live in rivers and mangrove swamps. They like lots of cover to hide within and/or behind. They occasionally swim in open water but prefer to lurk out of sight of potential prey or other predators. They seem to prefer dimmer lighting. And, keep yours covered. They like to jump.
Water: As mentioned, crazy fish live where rivers run into the ocean -- brackish water. I dont think you need a particular specific gravity in their water. Theyre very flexible in their need for salt in their water. In fact, they probably appreciate a change in specific gravity and pH from time to time. Frequent partial water changes also help keep their nitrogenous waste products under control. If you use artificial sea salt instead of plain old NaCl, you bump up your pH to the point that ammonia and nitrite present serious problems. Change that water a lot.
Wood: Wood reduces the light in your tank -- at least the hefty chunks do. Your crazy fish will glue up against it (usually upside down) and try to turn the same color as your wood. He strives to blend in. However, he may go to the backside of your wood and disappear forever.
Rocks: We like slate. A piece of slate leaned against your front glass will keep your crazy fish visible probably 25% of the time. He likes the shade and the security the slate provides. If you lean it against the side, hes very hard to see.
Fast Swimmers: When chasing food or when startled, your crazy fish can swim surprisingly fast. Unfortunately, when startled, hes very likely to smack into the end of his tank. Youll see some wounded lips and eventually youll see calluses if you keep pestering him.
Tank Mates: Feel free to house your crazy fish with non-violent fishes too large to swallow. Gouramis and barbs come to mind. Do not mix him with cichlids. Cichlids and crazy fish both get too territorial to get along together.
Foods: Crazy fish like all manner of small fishes on the menu. They also like worms and shrimps. Supposedly, they also eat flakes and pellets. Weve just never tried them.
