Topic: Lace catfish with patches of missing skin and worn fins.

[CobraR]

Hey all, my lace catfish Spot has some ragged looking fins and has developed what appears to be patches of missing skin on her flanks.  They started as white spots, then gradually became red and appear to be exposed tissue.  I ran a round of Kanamycin in the tank to help prevent a secondary infection and removed a cichlid that was picking at her sores.  I also removed a Balao-class submarine decoration from the tank after suspecting it of hitting her with a torpedo.

All kidding aside, I have noticed that the pH in the water was waaaay low, as in below scale.  I don't know what the pH is, but it is under 6.0.  The question I have is this: could overly acidic water cause skin/fin deterioration?  The cichlid I removed from this tank doesn't have any symptoms at all but I figure his scales would be more resilient than the lace cat's smooth skin.

[toddnbecka]

Yes, water being too acidic can cause problems for some fish, particularly catfish. The simplest solution is to toss a handful of crushed coral into a filter to raise/buffer the pH. It would also be a good idea to increase the size and frequency of your water changes.

[Aiptasia]

Yes, a pH crash where the pH swings too low can cause skin disorders just as you're describing that will mimic bacterial infections. Usually, these can be treated with water changes and in extreme cases, buffers added to the water (sodium bicarbonate). What I would do is do a 1/3 tank water change and monitor the pH and bring it up gradually. Our aquarium articles section has articles for safely raising the pH of the water.

[CobraR]

Did a 50 percent water change, gradually started raising the pH, tried a handful of coral as toddnbecca suggested and the sores were healed up in days.  Thank you much.