Rant on Velvet
The species that make up the coccina complex of bettas, are among my favourite species of fish to keep. However, they seem to possess one annoying trait that can make long-term keeping (at least in my experience) a challenge.
That is, their seeming susceptibility to the pesky parasite, Oodinium or 'velvet'.
I like to think of myself as a dutiful and dedicated fishkeeper. I am careful with my parameters, mindful of my fishes' needs and only share equipment between one or two tanks. When I kept splendens, I had velvet once, and that was because it was brought in by an outside fish after I didn't quarantine.
Anyone who has dealt with velvet knows it is nasty. I have had fish develop quite severe infections around the head and gill area due to the irritation caused by the parasites. The medication and treatments used for velvet can also be hard on fish, particularly on the fry and juveniles that seem especially vulnerable.
Some sources say to avoid velvet, you should not remove fry from the parent tank. However, in some cases it seemed to be that my fry ended up with velvet anyway and then passed it onto their parents! Very frustrating to say the least.
Also, due to the natural iridescence of these species, I find it to be very difficult to make a diagnosis early on. Usually the first place I notice signs of infection, is the fin membrane and around the gills. Therefore, the parasite usually has a firm foothold by the time treatment has started.
I have read that leaving a copper wire in the tank can help prevent velvet in susceptible species. However, I was always under the assumption that copper is much more toxic in a low pH environment, and I am more afraid of losing my stock to copper poisoning than to velvet.
Oddly enough, it is the two wild-caught pairs of fish I own that are the only ones in my fish room that have not suffered through this disease at some point. I would have thought they would be more sensitive than the captive bred fish, but it seems the reverse is true.
Hopefully in the future I can clear this out of my fish room for good. Having this crop up again and again is probably the one thing that is going to burn me out of the hobby.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.