Aquarium keepers struggle to diagnose fish health issues
20 posts in the last 60 days, all from r/Aquariums.
“I have small chili rasboras in my tank and yesterday I added an extra sponge onto the lip of my HOB filter because the normal current was way too rough with them (like they were getting thrown to the bottom by the current), but now there's a lot of biofilm on top and I don't…”
“In the last few days, I have had one of my 7 Harlequin Rasboras start to show signs of SBD. He is still schooling, still active, but noticeably swimming on an angle, and he almost appears to bounce because he cannot just maintain a position in the water like the other 6. My 20…”
“So ive gotten these a few weeks ago from my local pet shop, they seemed fine for awhile then one of the smaller seemed to have lost is side fin and all that was left was a nub. The fish sadly passed a day later and now another fish seems to have the same issue, From what ive…”
Multiple aquarium hobbyists are seeking help identifying and addressing various problems with their fish, including bent spines, unusual markings, and potential diseases. This indicates a need for clearer guidance on aquatic animal care and disease prevention.
SOURCES (27)
“I have small chili rasboras in my tank and yesterday I added an extra sponge onto the lip of my HOB filter because the normal current was way too rough with them (like they were getting thrown to the bottom by the current), but now…”
“New fish keeper here, My Harlequin Rasboras (10 of 12ish) have developed big bloated bellies over the last couple days. Any idea why? I've only had them for two weeks. Too much food? Constipation? Parasites? I'd maybe guess full of eggs but what are the chances I have almost all females? They weren't marked as a particular sex at the LFS. Thanks! submitted by /u/aaroneouz [link] [comments]”
“Hi everyone, We lost one of the harlequins in a 200L tank last week after he developed a bump on his head and a white layer which expanded down one side of his body. We started the NT Labs antifungal treatment on advice from the LFS but clearly not fast enough. The last three photos are the original patient. The week's course finished on Saturday, and now another harlequin has developed a similar presentation. I know you're not meant to use the NT Labs treatments immediately after finish”
“Looking at the topmost neon. A quick google about a bent spine like this says potentially Neon Tetra Disease, thought I would come to the experts. They have all looked normal until about a week or two ago, when I noticed a slight curve in this one, and slight fading of colour in another. Should quarantine him? Any help is appreciated greatly. 10gal, 1 rosy barb, 3 rummynose tetras, 4 neon tetras. submitted by /u/Picklefan92 [link] [comments]”
“I recently got a couple more cpds to finish off my tank and I noticed one of them did not seem well after a little while. I thought he was just a little deformed but his back is very hunched and his belly is sunken in. Definitely was the weakest fish in the tank so he was like this when I got em. Now is quarantined. I don’t see any lesions, I stick my hands with open cuts in the tank all the time and I’m still alive and well so I’m leaning more towards parasites than TB. I am about to euthanize”
“In the last few days, I have had one of my 7 Harlequin Rasboras start to show signs of SBD. He is still schooling, still active, but noticeably swimming on an angle, and he almost appears to bounce because he cannot just maintain a position in the water like the other 6. My 20 gallon tank is decently planted, has been up and running since May 2025, and is very stable. 7.8 pH, 0 0 and nitrates rarely get into the 20+ range. dGH 8ish, dKH 5ish. Early on I had 3 fish losses(2 Panda Corys, 1 Panda G”
“So ive gotten these a few weeks ago from my local pet shop, they seemed fine for awhile then one of the smaller seemed to have lost is side fin and all that was left was a nub. The fish sadly passed a day later and now another fish seems to have the same issue, From what ive looked up it could be something called saddleback/columnaris im not too sure and am new to keeping this kind of fish. submitted by /u/TLKOOL11 [link] [comments]”
“I ordered these rice fish online and the others are completely fine however this one which is much thinner and has a bent tail has just been floating at the top not really swimming around , my main worry is that if this is genetic I don’t want this to get passed down need some guidance submitted by /u/Working-Permission13 [link] [comments]”
“Hi all, I noticed these weird marks/discoloration on one of my Harlequin Rasboras. Water parameters are at the same levels they were when I first set up the tank. The marks don't appear to be 3-dimensional? Photo 1 was from yesterday. Photo 2 was from today. I'm not sure if the lighting is playing a part but it does seemed to have improved a bit? submitted by /u/arktikrush [link] [comments]”
“My Bolivian ram came a week ago. It’s in a tank with rummynose and harlequin rasporas. Tank is 55 gal, 76F with no ammonia or nitrites. ~6.8 pH. This morning I found him like this. His gill is still moving. Any chance of saving him? He’s the centerpiece of the tank. Thanks everyone! submitted by /u/DynamicStochasticDNR [link] [comments]”
“I noticed about two weeks ago one of my female Bosemanis developed what looked like a few white scales on her side. I figured maybe she got nipped by one of my Kribensis or possibly my male Bosemani just got a little rough with her. Recently it’s gotten much worse and parts of her body are getting darker. Now, she mainly stays in the back by the heater and doesn’t eat much. Around this same time, my male Bosemani started losing his brightness, is barely eating as well, and mainly stays hidden in”
“One of my glofish tetras suddenly seems to have an arched back and a skinny appearance. Had them since last December, and the fish has been OK since then. Just noticed this today. Is there a way to help my fish? submitted by /u/aspie_electrician [link] [comments]”
“I’ve had this sailfin tang for aboit a week. Got him from a LFS and he had been doing relatively well but I noticed today he’s been laying on his side. Not completely but like tilting on rocks and is now refusing to eat. I checked my parameters and they read perfect. Salinity is sitting at 1.025 per usual. Every fish in my tank is doing well but today this one is being odd. Help? submitted by /u/Expert-Tree-8703 [link] [comments]”
“It won't swim right , won't eat, and looks very thin. They are some weeks old and I recently noticed this one thinking it's dead but it swam away when I got closer. I even moved it to a separate area and tried to feed it but it still won't. I'm not sure but it also looks different from others too.. submitted by /u/blue_jellyy [link] [comments]”
“i have a neon tetra that i got this month, who i just noticed has a crooked spine. im not sure if it recently developed, or if i just didnt notice before. he has vibrant colors, is showing no lethargy, no bumps, no swim bladder issues, and no fin rot. if he isn't showing any other symptoms of NTD, is is just a deformity? what is the next reasonable step? do i have to euthanize? the water peramiters in this tank have always been good and stable. sorry for the blurry image, i just put him in a”
“Hi all, just need some advice for one of my celestial pearl danios/galaxy rasbora. I’ve kept a group of these alongside Cherry and amano shrimp in a heavily planted tank for around 2 years and have never faced any issues, up until now. Over the last week, this little guy has not been eating at all and is just completely unresponsive to food. He appears as if he is struggling to swim and sits just above the filter at the water surface 95% of the time. There’s been no bullying going on from any of”
“Got a bunch of young harlequin rasboras from Petco a couple days ago, I noticed right away that a couple of them have what looks like a dislocated jaw. At least one of them with a wonky jaw was still able to eat yesterday, but today the one in the picture either couldn’t eat, or was missing the food when he went to grab it. 2nd pic is of a normal rasbora for comparison. Anything I can do and will they make it? submitted by /u/justmonki [link] [comments]”
“I recently had a decent BBA outbreak in my tank. Ive noticed my chameleon whiptail pleco has started growing gray fuzzy patches on its face/eye areas that look like BBA. Can anyone confirm this is BBA? Its gills are red too, but maybe its a regular fungal infection? The reason my outbreak happened was because of low flow and I corrected it, but the pleco sits motionless buried in the sand all day because its nocturnal which is why I thought maybe the BBA started growing on it. Its in a hospital”
“Hey guys. Noticed this red patch on one of my Lambchop Rasbora this morning. Any clues to what this might be? They've been in a 100L heavily planted tank for about a week, with 10 neon tetra, 10 pygmy corydora, 4 mystery snails, 2 BN Pleco and about 50 shrimp submitted by /u/ThicccThighss [link] [comments]”
“I noticed that two of my danios spines have started to curve over the last month. I have been testing the water and nothing has changed from the normal parameters. I’m wondering if it is a mineral deficiency? Any advice would be greatly appreciated submitted by /u/Forgetmeknottty [link] [comments]”
“So I got the yellow ones a few days before from petco they were the only ones they had there was three one was in bad condition but I tried to save it and couldn’t. As the 2 got better after a few days I went to return the one that passed. And I saw they had just gotten a shipment of black ones so I was like why the hell not. Now like the first day or so they didn’t surf but I guess after they got comfortable they started doing it. Now the tank has gone through big changes, like I did a API pima”
“Noticed a small spot of discolouration yesterday, but he was acting absolutely normal. Today it’s expanded rapidly, although he’s still acting normal. Can anyone please help me identify this or give me any advice? I’ve removed him to a quarantine tank, but I’ve never had to deal with medication before. In addition, if it is a disease, how do I “sanitise” my normal tank? submitted by /u/RatFinkaBooBoo [link] [comments]”
“Is this a sign that it might be sick? I just noticed that its body is slightly bent, and I’m not sure if it’s caused by stress from shipping. The other ember tetras that came with it look completely normal. It’s still active and doesn’t seem lethargic or anything. I haven’t put it in my tank yet because I’m worried that it might not be safe to introduce it while it’s in this condition. submitted by /u/Working-Tour1750 [link] [comments]”
“I picked up some Harlequin Rasbora from my local fish store, and it wasn't until I got home I noticed this guy. The batch look pretty you g based on their size, but this individual has a very bent spine. He is swimming and eating fine, so wasn't sure if this is just a defect, or an illness? submitted by /u/_Time_For_Plan_C_ [link] [comments]”
“Today when feeding the tank i noticed one of my rasboras was missing, and found him on the back of the tank hiding. He doesn't eat and is very skinny. Hides on the back of the tank (almost can't take a picture of him) and is separated from the others. Did some tests and they came back normal. Some context: I got these 3 kubotai rasboras 5 months ago with a promise from the shop owner that he was going to get me more of them, cutting the story short, he never got another kubotai rasbora a”
“Has anyone had issues with galaxy rasboras having bent spine? I’ve been noticing it more and more lately and was wondering if I’m doing something wrong. There was a group of 10 I owned, 5 girls and 5 boys. Unfortunately two boys started showing signs of scale rot so I treated the whole tank with Esha2000, they started to look better but then worse and then they started pineconing, I waited a bit more to see if they show improvement but they didn’t and I euthanised them when it looked like a poin”