Hi! I'm looking to get some helpful feedback with an issue I've recently experienced with my Dogface Puffer. I've had him now for a little over a month. He's a hardy fish, eats well, swims a lot, and gets along with all life in the tank.
The tank is a 38g eclipse, live rock, fish only. I do a 5g water change every 10-14 days. His tank mates include a diamond goby, neon goby, false percula clown fish, and a lawnmower blenny. All fish are juvenile. Additionally, we have one emerald crab and six small hermit crabs.
Recently, I've noticed that my puffer has changed in color. He's normally a stone gray with black spots. Lately, for the past 8-10 days, he's been a darker color, almost black at times (see photos at the bottom of this post).
I saw him change color not long after we picked him up. It happened shortly after he got something stuck to his body inside the tank. I helped him shake off the impurity and his color returned to normal. I'm aware that they change color as they mature, and also due to stress. This change seems abnormal, in that it has lasted a particularly long time, and I cannot figure out what might be the catalyst.
He also has something on his eye that I have not been able to identify. It looks like a grain of sand. We've thought that it may be some kind of cyst... it looks like a white head on the skin near his eyeball. This anomaly is also seen in the photo of the puffer with his darker color.
I've recently had my water tested (as I do after every water change) and all levels are normal, with exception to nitrate levels, which are slightly to moderately elevated at "15-20" (quoting the kid at the fish store). I did a 5g water change a couple days ago - haven't had the chemistry re-tested yet (will do that tomorrow), but it was done to bring down the nitrate levels. The water gravity is 1.023, and all other numbers (nitrites, ph, et al) are within healthy parameters.
His diet consists of frozen brine, live ghost shrimp and New Life Spectrum Marine Formula (small sinking pellets). Last night we tried clams in the half shell (frozen) to see if he was interested in working on the shell to cut his teeth. He wasn't overly interested in the shell, and the meat seemed a bit chewy for him, as well as far too much meat due to his small size.
I've also noticed a bit of twitching: a couple left/right shakes. And sometimes he'll dart from his position to a hiding spot, but comes out almost immediately. He seems at rest and peaceful most of the time. But out of nowhere he seems to become possessed. He does not attack any of his tank mates, and they do not attack him. Occasionally he will also twitch his gums (ala Rocky Balboa) and show his teeth. Otherwise he's friendly, eatling well, and social.
Any ideas what could be causing this? I was actually beginning to wonder if he might be constipated. Any and all help would be greatly appreciated.
Abnormal Photo: Note the dark color and foreign object type speck in his left eye...