I have this oscar who has two holes on his gils, one on each side. We just do not know what it could be. We talked to someone at the LFS and they suggested it was HITH. Can anyone help?

YIKES I forgot the picture! Actually, its been so long I forgot how to add the picture! DUH! I will get it up ASAP

Ok, I finally figured it out. I am toooooo silly!! Like I said before, he has one on each side of his face, on the gills.

My personal opinion is that this is lateral line erosion/Hole in the head. (Also oscars are very prone to this!) Nobody really knows what causes it but one theory is poor nutrition. I am inclined to agree with this. I work at a fish store and someone brought in a donation fish I believe was starting LLE. We feed very high quality foods and live tubifex, keep him in pristine water with no other fish and it has drastically improved. The biggest concern is secondary bacterial infections. What are you feeding him?

Here is a site with some good pics- http://www.flippersandfins.net/HITHarticle2.htm Look @ the second photo, I would say this is very close!

What are your water params?

Hi Kimberley. What you have there is the stunting effect of growth inhibiting hormones. Fish generally exude pheromones which when allowed to build up to high enough concentrations in the water will suppress the fish's growth. In goldfish it stunts the entire fish's body, keeping it small. In Oscars on the other hand, it only affects portions of the fish like the gill plates and mouth which stop growing while the rest of fish keeps growing. A weird phenomenon.

So basically the bit on the edge of the gill plate which looks like an indentation is the bit that has stopped growing and isn't keeping up with the rest of the fish as it grows. Another sure sign is if the lower jaw starts looking disjointed or bent out of shape as one side isn't growing as fast as the other. If the jaw distorts enough eventually the fish won't be able to eat any more.

You can't cure what's already happened, but you can prevent it becoming worse via simply doing more frequent water changes to keep the pheromone levels down, just like keeping nitrate levels down. In fact, use the nitrates as the measure and try and keep them below 20ppm at all times. Oscar breeders actually suggest a large tank (ie, 55 gallons per fish) to avoid this problem without having to do such frequent water changes.