I am new to the forum so if I miss anything I'm sorry and will answer any questions to the best of my ability. I'm a n00b at fish keeping, so I am just starting to learn a lot.
I have a 5 gallon tank, almost a month old. water paramaters tested every few days, all is well.
I did my last water change on Sunday, 25%, tap water treated with aquaplus and adjusted to the correct temp so as not to shock the fish. also using cycle at least once a week. Since getting the fish I have treated for fungus twice, once because I had just bought the fish and the next day the tank at the pet store was infected, so I didn't want my fish to get sick. the second time, one of my smaller neons clearly had white fuzz on his mouth. its been almost a week since I finished the last treatment, and it seems to have gone away.
I got a new filter a few weeks ago because one of my rasporas managed to swim up it and badly mangle itself. currently using an Elite filter that goes up to 10 gallons, using it on the lowest setting.
So, I lost one of my black neons yesterday after work. I have had two of the black neons for 3 weeks, they have been very healthy before a few days ago. the neon that just died started swimming strange 2 days before, he was having trouble staying upright and was swimming in the corner with his head straight up in the air and not eating. I fasted the tank for a day and a half and fed them some blanched peas. he appeared to be getting better, but then I found him dead at the bottom of the tank when I got home from work yesterday. I am still getting used to having fish so I suspect I may have overfed them and not realized :(
Now another one of my neons is acting strangely. He has been hiding for a while now, he tends to like hanging out behind the larger plant and is a bit territorial about it. he was still eating up until last night, he used to dart to get the food and then go back to his hiding spot. I also have seen him schooling with the others at times too so I figured he was just a bit anti-social. Today he would not eat, I feed the fish twice a day, once at 7:30am and again at 7:30pm. I have an auto thinger to turn the light off and on, it comes on at 7am and turns off at 9pm. I am looking at getting some floating plants to tone down the light a bit because I hear tetras prefer that.
So, back to the black tetra. Other than the hiding and not eating I noticed his dorsal fin is kind of slicked down today. he also had some slimy stuff hanging off his butt that I thought came from one of the snails or something, they seem to slime in the tank. He is also losing color, he looks pale and less black than usual.
The rest of the fish are acting normally. I notice a bit of domination on the part of one of the neons, he is a bit of a bully but it has been toned down a lot since getting the other neons and black neons in there. but they are all eating and schooling. the one raspora that has survived is pretty normal and darts around the tank and eats from the top. (the other two died in accidents, one jumped out and the other swam up the old filter.)
I realize I don't have enough of each species for schooling fish, but I was a bit misinformed before buying. I have been doing my best to help with that, I did have 3 of each kind of neon and 3 rasporas.
I also have a black neon with part of his face missing, but he was like that when I got him. I think it is an old injury because in the few weeks I've had him he is pretty normal and it has not changed at all. he does swim a bit to one side but I think its because one of his eyes looks smaller than the other. My theory is that he has some seeing problems on that side.
sorry for all the details... I have been reading a lot of fish forums and honestly, having fish die has made me really paranoid. I don't want to lose another one if I can help it! I am starting to get attached to the little guys, but I have buried one too many at sea in the past month and I want to prevent more of that!!
oh! also. temp is generally between 25 C and 26C, it tends to go down a bit at night and up a bit during the day. if I missed anything let me know.
the attached pic is of the black tetra that I am worried about. the slimy hangy thing had fallen off by that point.