Loaches Online Forum

I have an identified Gastomyzon who seems very "happy" in that he moves all over the tank and seems to almost always grazing.

I saw a couple of profiles for hillstream loaches that said they were schooling species. Should I be getting mine some buddies to make him more comfortable?

Also, the pictures here often have the fins extended. I have never seen my fish's fins, always pulled flat against himself. Is that a sign he's not as happy as I thought?

Kylie

Hi Kylie and welcome to LOL.

Whereas some hillstream species such as Homoloptera do best in groups, Gastromyzon and other Sucker-bodied fish are not shoaling species. They will live reasonably well by themselves but it is far more rewarding for the hobbyist to see the interactions between fish when several specimens are kept together.

The photos that you see here of fish with the fins opened are usually obtained by chance or by exhaustive waiting for the fish to move from rock to rock. Once you understand their methods of movement one can anticipate a move with open fins and hopefully catch it on camera.

Generally, they keep their fins clamped not because they are unhappy but because in nature in the fast-flowing water it minimizes drag, so it is easier for the fish to maintain station against the current.

Martin.

Hi, Kylie,

In my tanks, raised dorsal is almost always related to attempts to scare other hillstreams. Here are a couple of photos that show this:



A Gastro on the right is moving on a sitting Cheni (who also happens to be the Alpha fish in the tank at the moment, but the Gastro does not know this yet). Gastro's dorsal is up, Cheni's is down. Now, a few seconds later, Cheni realizes that he is under a challenge and we see



Now the Cheni's dorsal is up, and the Gastro is sufficiently impressed to get out.

I think it would be quite unusual to see them raising fins if there is only one hillstream in the tank...there is nobody to impress/threaten.