I have a very young Cochinchinensis (Fangs) puffer, all of about 1.5 inches long. After nearly a week at home, I noticed the red start fading from his eyes. First the pearly red sheen wore off the entire lense of the eye, giving way to a flat red/orange Iris and a black pupil. Now that coloring has faded further to a simple thin, red ring around the entire eye ball. Now his iris is yellow/gold with no noticeable metallic sheen like other puffers with yellow eyes have. If it weren't for the red ring circling his entire eye I would never had known he's considered a "red eye" puffer
I searched diligently online for any similar situations or info and found nada. So I'm unsure what could be causing this change, hopefully the answer can be found using the following information.
Tank: 20 gallon long
Temp: 78-9* F
Parameters: Am-0 Nit-0 NitRA-10
Addtl in-tank: Tank was cycled when puff was introduced, but the BB needed to ramp up so have been adding SeaChem stability daily, and 25% WC every other day (M,W,F, SU) to keep water clean while filter catches up. Dose SeaChem Prime on the off days when the water doesn't get changed (TU,TH, SA). Also something that may be affecting the water is 1 (new) large piece of spider wood, leaching out this clear jelly substance that I keep cleaning off. Lfs says it won't hurt the fish, but it makes we worry bc it obviously gets in the water. My substrate is CaribSea med grain sand.
Diet: Primarily (thawed) frozen blood worms, live ghost shrimp, and live snails.
There is no other signs of illness or distress, but the fact that the eyes started changing a week into my care, and have stayed this way for another 7 days now, without reverting back to the original opalescent red, makes me think something is amiss.