Sad Kuhli Loach. Need Insight.

[Kaligma]

Just looking for advice about what could potentially be happening to one of our Kuhlis. This duder has been super thin on their belly for about two weeks. Originally they had a couple red sores on them too. We got API's Melafix and the red sores went away but their belly is still so thin. They spend most of their time on this Anubius wood and a loach friend has been consoling(from what we can tell and hope) them for the past two days. The larger loach is struggling to breath, as well. Seemingly taking large breaths, as their gills open wide.

We had hoped that the Melafix would rectify the concern but they continue to have the reduced skin thickness. We got all of our six Kuhlis at the same time and one of them was significantly larger than the rest. Could it be a possibility of old age for our fishy friend? We're at a loss and am curious about your insight, if any.

It's been such a good time with our scaley sidekicks and our tank and we just want to make sure that if there is anything that we can do that it happens to the best of our abilities and/or if we should take more drastic measures. There are no other fish that seem to be affected and that's why I was leaning towards the possibility of old age.

As always, thank you so much.

You are an amazing community and we are grateful to be a part of it.

 

[Ghelfaire]

Medication can be hard on scaless fish. Is he eating?
Old age is possible, how long have you had him?

 

[Kaligma]

It's difficult to tell if he is eating or not. As it's hard to spot these guys eating, in general. We've had the loaches for about 3 months but when we got them one of them was full grown(or appeared to be). So, I'm not certain of their proper age.