I recently introduced an Elbii (Red-Striped) Angel to my 55q aquarium. The tabk is FOWLR
with the possibility of some hardy inverts to be added later. Currently I have an adult algae blenny and a juvenile/sub-adult Clarke's clowfish.
The new angelfish appears to be healthy and vibrant, and it has eaten several kinds of food eagerly. However, under the lights of my home aquarium I can see that one eye is clouded, like a cataract. The Elbii has bright yellow rings around the eyes, so I can see that there is no discoloration anywhere except the eye itself. The eye rotates normally in the socket. This is only in one eye, and there is nothing else physically wrong with it.
Until they were seperated, I also noticed that both the clownfish and the blenny were giving the new arrival unwanted attention. This wasn't exactly aggressive, but involved playing "chicken" with the angelfish by swimming toward it very fast and then veering away. The blenny also insisted on sitting very near the angel and following it around. I initially divided them but the blenny spent and hour or so pushing against the divider, and the clownfish seemed to be spending a lot of time near the divider as well. They have both recently been moved to quarantine buckets
What could be causing this eye problem? Is it contagious? Also, is this a normal level of aggression towards a new arrival, or is it something to look out for? The clownfish was very docile towards it's previous tankmates, and I don't see what a blenny could have against an angelfish.
I can try to take a picture of the clouded eye if that's necessary