Fighting Hillstream Loach

[Hmarie37]

Good evening all! I have 3 hillstream loaches, 2 of which I got from my LPS yesterday. One of the new ones has been constantly chasing after the other two. My first loach was so calm before I added the other two to the tank. Now that this one menace is chasing them both down all 3 of them are zooming around the tank. Is this usual behavior for Hillstreams? If not, any suggestions for the aggressor?

 

[Colin_T]

You probably have 3 males and the dominant one is telling the others the tank is his territory. If it continues for more than a few days you will need to separate them.

 

[Byron]

Like all loaches, the species develops an hierarchy. What you see is certainly not at all unusual, and need not end in disaster. Generally peaceful, in its habitat this loach lives in large groups; males will "defend" their territory (selected on the basis of available food) by "topping." When a second male invades another's territory, one fish tries to cover the other in a test of strength, termed "topping." There is rarely any damage inflicted, and one fish eventually retreats. The dominant males claim the best algae areas as their territory, while females tend to congregate in other areas. This fish must be in groups of at least six, or it can be very withdrawn and inactive. You might consider two or three more. They need stronger water current, and cooler than normal tropical temperatures, and lots of algae-covered smooth rocks. River rock pieces placed in a bucket of water in direct sunlight will soon supply this, and they can be replaced as needed.

 

[Hmarie37]

Here to give an update that it did seem they were marking their territory. Everyone is leaving peacefully in the tank now and looking so darn cute!