Hello,
I am a beginner and i got a 10gallon tank with two oto cats and some tetras and guppies in it. I have been reading about all the different diseases the fish can get and I just noticed that on this oto cat - george, on the right underside where the gill is, there is something that looks like a pimple or a lesion or some sort and it looks to me like in the middle of this red thing (its more pink than red on the other side) there is a black dot. i dont know if i m just being paranoid because of all that reading i did today about fish diseases...but i m pretty sure it looks way redder today than yesterday. i wonder if he's just injured cuz he scraped himself on something or something else more serious is going on...? other than the redness and it looks like a little bit of swelling....cant really tell exactly....theres nothing else different about him...theres no white dots or rotting or patches or anything like that any else where. none of the other fish.....not that i noticed so far...has anything abnormal about them. Also he seems to be breathing quickly continuously and i know thats a sign that something is wrong. i checked the water and theres neither ammonia nor nitrite and ph is 6.9 while nitrate is 10ppm...he gets fed vegetable flakes and tablets. i have had him for just over a month. the water is well aerated cuz i have had the bubbler going for hours. Can anyone please help me...i m getting worried...i have attached some pictures so you can see what it kinda looks like (i tried my best to get a clear enough picture)...

I am a beginner and i got a 10gallon tank with two oto cats and some tetras and guppies in it. I have been reading about all the different diseases the fish can get and I just noticed that on this oto cat - george, on the right underside where the gill is, there is something that looks like a pimple or a lesion or some sort and it looks to me like in the middle of this red thing (its more pink than red on the other side) there is a black dot. i dont know if i m just being paranoid because of all that reading i did today about fish diseases...but i m pretty sure it looks way redder today than yesterday. i wonder if he's just injured cuz he scraped himself on something or something else more serious is going on...? other than the redness and it looks like a little bit of swelling....cant really tell exactly....theres nothing else different about him...theres no white dots or rotting or patches or anything like that any else where. none of the other fish.....not that i noticed so far...has anything abnormal about them. Also he seems to be breathing quickly continuously and i know thats a sign that something is wrong. i checked the water and theres neither ammonia nor nitrite and ph is 6.9 while nitrate is 10ppm...he gets fed vegetable flakes and tablets. i have had him for just over a month. the water is well aerated cuz i have had the bubbler going for hours. Can anyone please help me...i m getting worried...i have attached some pictures so you can see what it kinda looks like (i tried my best to get a clear enough picture)...
