Check water parameters. Color changes can be a sign of impending issues. There is also a neurological issue that causes fish to turn black. Either the pathways are pinched or diseased. There's not really much you can do if that's the case so rule out water issues first.It seems fine otherwise. I have had a group of 8 in my 70 gallon tank for a few years and this is first time I’ve noticed something like this.
Yeah I just did a water change about two weeks ago but I’ll check the numbers but I don’t think that’s the issue. He is the only one in the school that has turned.Check water parameters. Color changes can be a sign of impending issues. There is also a neurological issue that causes fish to turn black. Either the pathways are pinched or diseased. There's not really much you can do if that's the case so rule out water issues first.
A lot can happen in 2 weeks so "Just did" isn't really accurate. ( Just sayin' ) If it's not the water, you can try working with an internal antibiotic but again, the chances are slim that it will work. The reference material I have on this also claims that it could be a thyroid tumor which has had some success with reduction by adding iodine to the water. To diagnose this tho means looking inside the fish's mouth and looking for an inflammation at the base of the mouth under the tongue. Glass cats aren't that big to really do that tho. See if the fish has any kind of bulge under the chin that looks different from the other fish in the school.Yeah I just did a water change about two weeks ago but I’ll check the numbers but I don’t think that’s the issue. He is the only one in the school that has turned.