Iridescent Shark - turning clear and brn-red?

[BobFish]

30 gal tank, two freshwater iridescent sharks (only), nitrates ~20 nitrates ~.5 PH 7.2. Last water change about a week ago.

Fish are about 6 years old. They've been doing good lately, no fin rot. Active and eating regularly.

I noticed that one of them has been getting lighter (less black colored). Usually that happens when they have some immediate stress like panic from being cleaned. The last couple years they have been more curious than worried when I clean them and they don't panic or even mind the process.

I was not too worried but I noticed today that the lighter guy was spending some time sleeping on the bottom. They had a couple years where they did that a lot, but the last year they've been up 24/7.

When I fed them he woke up and came to eat but I see that his body looks reddish brown all the way around the gills/main area and also along his body towards his tail. He may also be losing weight although that's hard to judge. He has certainly been eating well... they are always ready to eat.

I don't know if the reddish-brown is just his internals showing through because he's become so "clear" in his body or if he's got some strange illness I am not familiar with.

Thoughts?

 

[GhostKnife]

What do you mean when you clean them...??? Partial water change?

 

[BobFish]

What do you mean when you clean them...??? Partial water change?

Yeah... I don't hand wash them

Partial water change, clean tank sides. Filter is changed on alternating schedule at least a week from any water change.

This guy is really getting clear in color, I'd rate him as "translucent".

 

[Dano01]

Could it be old age setting in and possibly lacking some nutritonal need?

 

[BobFish]

Could it be old age setting in and possibly lacking some nutritonal need?

Maybe nutrition... perhaps I should broaden their diet. As for old age: my oldest irridescents lived until they were 22, so I am hoping these guys have a way to go.

 

[Zagz]

Any chance of a picture to help us help you?

 

[BobFish]

Any chance of a picture to help us help you?

I'll try. Capturing him will be difficult.... when he's up, he's usually moving. When he's sleeping, he's down in a gully where I can't photo him very easily.

FYI - I've been working the PH back to neutral. He seems to be more active and his color is better, but not really "normal" yet in either respect. I don't know that the PH is actually related though.