When you purchase a group of clown loaches for your tank you'll soon notice that the clowns establish a hierarchy (pecking order) with Alpha and Omega Loaches. Contrary to most species the clown loach Alpha is generally a female. As you may have guessed, the hierarchy is created through displays of dominance and fighting. It can be unnerving for the aquarist to have fish fighting, but you have to let them arrange the pecking order and the fighting will subside. Sometimes, the suboccular spines will cause nicks and scratches on the other clowns and clowns may even change colour during scuffles, but it is all for the greater good; the establishment of the hierarchy.
Another behaviour of the Clown Loaches that is potentially distressing for the beginner aquarist is the clown's strange sleeping habits. They have been found sleeping in strange places and at weird altitudes. If the clown fish are laying upside down behind some aquarium vegetation, they are probably just sleeping. If they are laying on their side in a cave structure and they aren't moving, they are probably just sleeping. It can be upsetting at first, but you'll get used to it.
Being the gregarious species that they are, clown fish will do what is called "loach-dancing". Often the dance is vertically oriented and the members of the group swim up a short distance, then tumble down over each other and then swim up again. They can continue this dance for quite a long time. The clowns may also wiggle or bounce around and make skittish movements that could be construed as dancing.
Aside from pure entertainment, clown loach behaviour can be used to diagnose certain problems in your clown fish tank. Clown loaches are very observant and tend to do what they see other fish doing. If you have shy fish that tend to hide a lot, the clowns will observe this behaviour and may mimic it. Include docile, gregarious fish in your tank and your clowns will come out of hiding as long as the water is comfortable for them. Also, remember that in nature, clown loach fishes are found in fast moving, clean streams and rivers, so maybe recreating that sort of environment in your tank will help your clowns join the party.
Sometime after you add the first clown fish to your tank you might hear a clicking noise (sometimes so loud you'll think the tank cracked!). When clown loaches are excited or eating they may make clicking noises by grinding their pharyngeal teeth. Nothing to worry about though, it's only natural.
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