Angelfish with one bulging eye - pop eye??


Hi - please help,

My son yesterday evening noticed that our silver angel fish had one eye bulging out. He is usually very healthy, eats well and had no problems in the past. Looking through the other post online, my initial guess is it is pop eye due to injury but comparing it to other photos, i'm not so sure now.

Other fish in tank are: one other angelfish - orange - no fighting between these two - possibly same sex - female
five Stendkar discus - various sizes (2 small, 2 medium, 1 large)
one betta
one zebra danio
5 five banded barbs
2 corydors
4 guppies

temp : 29 C (only just increased last week from 28 C - explanation below)
180L tank, gravel substrate, few ornaments, external cannister filter fluval, LED lights, 3 plants but not growing well. Tank established Jan 2021. Perform 50-60% water change weekly on fridays and clean filters beginning of every month. UV lamp via filter runs 2 hours per day. Last new fish to be added were guppies about 2 months ago.
Ammonia - 0
Nitrite - 0
Nitrate - 40ppm (my tap water comes out with this much nitrate)
pH 7.6 - 7.8

Fish are fed twice a day with Stendkar brand beefheart and Sera growth granules.

Just last week, I lost one discus and one male orange angelfish. The discus had white pimple like spots on the top of the head near the eyes. Treated with melafix and it went for a few days but returned. Kept treatment ongoing for another week but discus died. Initially thought it may have been an injury or something and the white spot like pimples were like scabs. 100% sure it was not ich because it was localised in one area and the spots were big. This discus also went off his food during this time. Now, I am thinking possibly hexamita. Poop was not stringy but not sure if brown or white in colour.

The male orange angelfish had an injury on its side (this angelfish was always very territorial so frequently in fights). Happened same time as discus getting white spots so treated with melafix. The injury got better but this angelfish was breathing heavily and went off its food. Assumed possibly gill flukes so treated with flubendazole and increased aeration but never recovered and eventually died.

Please help with my silver angelfish. Last night, I added one tablespoon of API salt for every 20 L of water (ie 9 tablespoons for 180L). I am based in the UK so cannot buy antibiotics from LFS but I do have access to human antibiotics if that is only cure.

I have not set up a hospital / QT tank because in the past, I always get an ammonia spike and get forced to move the fish into the main tank. Thank you in advance to all who reply.


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Rose of Sharon


Welcome to Fishlore!!!

What beautiful fish you have!!!

I am in no way an expert on angelfish, but I think that the salt along with the increase in temperature will help along with some frequent smaller water changes in order to keep the water pristine.

Also, to treat your angel's eye, you can do a couple of epsom salt baths to help with the swelling. Use only pure epsom salts with no additives or scents. Use a separate container, and dissolve one tablespoon of epsom salts into one gallon of water. You can use some tank water for the bath, so that the temp of the bath matches the temp of the tank. Leave the fish in the bath for about 15 to 20 minutes. You can try one to see how things go. If the angel gets too stressed, put it back into the main tank. If he/she is ok in the bath, you can do one daily until you see his/her eye getting better.

I am not a fan of melafix, but I know that it may be the only thing that you can get. Since it's not a true antibiotic, but rather is tea tree oil, I find that it works as an antiseptic of sorts only.

I'm not sure of a diagnosis, as far as what is causing the issues. Maybe someone else might be able to help with that. I do know that mixing angels and discus can be somewhat precarious at times, but you have a pretty big tank, so hopefully that is not an issue. And zebra danios are known fin nippers, too. But you know your fish better than anyone, and you would know if there is an agression issue.

I hope this helps a little!!!!


Thank you for the reply Rose of Sharon.

Last night, I did a 60-70% water change, vacuum clean the gravel with syphon and wipe down the sides of the glass and re-added salt based on new dechlorinated water going in. I will continue doing this for the next week or two before doing 10-20% changes to remove the salt.

Question - Maybe an obvious answer but how can I tell if my angelfish is getting better with regards to 1 tbsp salt / 20L or increase to 2 tbsp / 20 L. The eye still looks the same but now has a white layer of film over the whole eye and the excess white inflamed tissue around the eye is beginning to flake / peel but still bulging out. I couldn't get a picture of the eye but now I have a second problem with this angelfish - It had a fine string of white long poo - is this due to stress or a secondary internal infection? She has also stopped eating. I'm assuming best course of action is maintain the daily water change?

Also, incase it is is hexamita, I read maintaining a higher temperature of 29 - 30 C, especially with discus is a way of controlling it (assuming hexamita are part of the natural gut flora within fish and hence no way to get rid of it). I know some of my smaller fish have a temperature limit of 28 C but again I read this is more due to lower oxygen levels in warmer water and increasing aeration will reduce the stress of the higher temperature.

My main goal right now is to protect my bigger fish because it feels like the grim reaper is visiting my tank!!

Regards to the nitrate levels, my plants never seem to grow well enough and the higher temperature does not help. I am reading more about the pozzani filter but also came across the idea of using a Pothos houseplant growing outside the tank with the stem inside. Anybody with any experience in this who knows if this would work?

Again, Thank you for your replies and REMEMBER, FISH ARE FRIENDS - NOT FOOD!!


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I noticed in the last picture a long stringy poop that looks like parasites as well. I would treat that with medicated food just in case. As far as the eye, just keep what you do and see if it gets better, worst case you can go with erythromicyn which is very good for that
Good luck Asifd


I think that the main problem you have is too many quite large fish in a small tank. If you are dealing with Hexamita you need to get metronidazole, it is the drug used to cure giardias etc. in humans and dogs. I don't know how easy it is to get in the UK. You can find dosage instructions for fish online. I would be very careful about using a lot of different drugs without being sure of the exact condition though.

Rose of Sharon

I think at this point I would try putting the angel into a hospital tank to treat. If it does have some sort of parasite, or hexamita, that could carry over to your other fish.

Super clean water is an abslolute must.

I think that I would try one and a half tablespoons of aquarium salt per 20 L first before 2 tablespoons. Up it gradually.

You can always add an air stone to increase oxygen levels, if you need to.

Do you have access to something that will treat parasites? Something like Fish Zole? Or Fish Forte?

And I agree with TClare, the perferred med for hexamita is metronidazole, if you can get it.

It really stinks that you can't get what you need to treat your sick fish!! :(

One of the better antibiotics here in the states to treat bacterial infections in fish is kanaplex, which is kanamycin. I don't know if human meds act the same as fish antibiotics, but this won't treat parasites.

I have pothos in my tank, and they do help to keep the nitrates down. And the fish love to swim in and around the roots! There are pothos hangers that you can buy to attach to the back of your tank.

I hope this helps!


Hi all,
Carried out a 50% water change last night and wiping down internal glass. Still replacing salt in the new water. Also, started medicating tank with metronidazole based on 1g / 80litres of water. I have access to human metronidazole suspension and tablets - would it be ok to dose using suspension?

Unfortunately, woke up this morning to find my silver angelfish struggling and resting on the gravel against the glass. A few hours later, she passed. Also, the last of my danios ( my original batch of first fish in this tank) has also died. Don’t think the danios death is linked to the current problem - poss the meds, salt and temperature were too much for the little guy.

I will slowly cycle the tank on a daily basis to remove the salt based on 10% daily salt removal. I know i should continue to medicate the tank but this morning, my discus didn’t seem too keen on their food as usual. I’m guessing it is the effects of the antibiotics. Not sure if should continue with metronidazole for 9 more days.

Any advice would be appreciated. Thank you.


I always prefer medicated food when it comes to parasites because target directly where is needed. I use metro with focus and garlic guard to improve the taste. I also use frozen food. So far i havent had issues with this method. I personally dont like to put too much medicine in the water since the fish get stress so easily that goes backwards instead


I always prefer medicated food when it comes to parasites because target directly where is needed. I use metro with focus and garlic guard to improve the taste. I also use frozen food. So far i havent had issues with this method. I personally dont like to put too much medicine in the water since the fish get stress so easily that goes backwards instead
Yes, medicated food would be ideal. but may not be available in the UK. Also some fish with Hexamita may already be off their food and refuse to eat it. I am afraid I don't have experience with using this or other medications, I think there are others here who could advise better as to whether or not the treatment should be continued. Discus are notoriously sensitive and in any case should be kept at temperatures around 28-30 C.


HELP - just came home and saw the tank was cloudy, tested water parameters - ammonia 0, nitrite about 2.0ppm and nitrate about 20ppm.

Doing immediate water change 100% - water pumped in one end and out the other. Will need to add salt back in without knowing how much water has cycled to prevent big changes of salinity in water.

Any advice to prevent deaths due nitrite - I do not know of anyone with fish tank to borrow their bio media.

Please help.

I will clean filter media as well to remove any antibiotic residue to speed up nitrogen cycle - bio media in tank water and sponges in tap water.
I have also maxed out the air bubbler to improve oxygenation


I am trying to tag some people who might be able to help. MacZ , A201 , 86 ssinit


I agree that the tank is a bit small for a Discus community & that Discus do better in a species only situation.
The death of the first Discus was likely due to Hexamita.
I'm no a big fan of feedings any fish beefheart. It's not a natural food for a Discus. Maybe frozen Bloodworms, Brine Shrimp & supplemented quality Cichlid pellets would be a better choice.
I'm not enthusiastic about aquarium salt either.
The Angel evidently died from a bacterial infection.
I think the best course of action is to get the environment stable & as close to med & salt free as possible. Temperature range 84 - 86 degrees. Consider keeping an all Discus community. Two weekly 50% water changes. Keep very subdued lighting.
I think the OP did a great job following the available online treatment advice. Unfortunately things often don't produce as much success as advertised.
Take a deep breath & get a fresh start. Stay connected to the forum. Things will likely level out soon.


An update -

After three 70% water changes, I finally managed to bring nitrites down 0.25ppm or below. Also ordered API QuickStart from Amazon so hopefully use that from tomorrow evening to speed up nitrogen cycle.

Will check water twice daily and perform large water changes to keep nitrite levels down. Also started to cycle salt out at about 20% per day so by time tank is cycled, salt will be fully out.

To keep bio load down, I have removed my plants from the tank (decaying leaves) and will feed fish pellets only once on alternate days.

Thank you to all who replied to help and will be grateful for any other suggestions.

86 ssinit

Well all I can say is to many fish. 45g 5 discus maybe 3 angels a betta? And still more! This was never going to work. Don’t think hex your worrying about. It’s dirty water. Not just for the discus but for all of them. The beef heart mos definitely started this problem. Beef heart should only be fed in a bare bottom tank. If not removed it’s just going to rot. The pimples were bacterial nodes. Both discs and angels will get these and it means dirty water. The pop eye is another sign of dirty water. The discus need their water changed daily. Stop feeding beef heart. Just feed the cera granules.

All the meds aren’t helping either. Most meds do worse than they do good. I’m a salt user so for me you can go ahead with that. But first let’s see some pics of the whole tank and of the fish. How long have you had this tank running and how long for the discus and other fish.


What 86 ssinit says is exactly what I thought at first. I have a180l tank and I just can't imagine having all those fish in there. As well as too much bioload there is the stress factor caused by overcrowding, which will weaken immune systems and make them more vulnerable to disease. Any fish, but especially discus.

Healthy plants will help with the water quality, but not if there are lots of decaying leaves obviously. Perhaps you could get some floating plants? They really help to reduce nitrates and I suppose nitrites if they are present. I am very sorry about the angelfish and I hope the discus pull through, I know you are doing everything you can at this stage.


Final update - thank you for the comments so far and will take advice onboard.

Agree the tank maybe over populated but it’s a tank I have had from Dec 2020 and it started with small fish gradually moving to bigger fish because kept looking for showpiece fish and initially put off by discus due to cost and everyone saying very difficult to keep. The discus have been in the tank since May / June gradually moving from 3 discus to 6 in the last two months because read everywhere they are better in groups. As I lost the small fish, they are not being replaced so gradually moving to all discus tank with one species of small fish. So, it’s still a work in progress. The betta may soon be moved in tank by itself once I find a nice one that is good size.

The Stendkar beef heart I feed is not as messy as other cheaper brands I have tried. I vacuum the gravel weekly with 50-70 % water change and clean filter monthly. The filter until using antibiotics has never showed any ammonia or nitrites. The water is clear and clean so disagree with dirty water unless someone can define what is dirty water. Nitrates are high so will be fixing that with a pathos plant or pozzani filter soon.

Plants I have never had luck from day 1. They either don’t grow well or covered in diatoms initially and then black algae recently and decay and die. I have used fertiliser, CO2 and even cleaned them weekly but still had no luck. I have tried floating plants and they grew well but tank is in my living room and my son and wife didn’t like the look and shade the plants would cast hence removed. I’m assuming the black algae is due to excess nitrates but because the plants never grew well when I only had 6 danios in tank, I will give up on plants in water and focus on plants growing outside.

I have been told that it maybe possible to keep up to 8 discus in 180L tank with no other fish hence the angel / discus mix. Would 5 discus be happy in my tank or am I better opting for a group of 6-8 because always told discus will only do well in groups of around 8?

I have posted a picture of the whole tank too to get your opinion - please be nice . The nitrites and ammonia are zero now and I have gone back feeding as normal. Still testing daily but pretty sure tank is back to being fully cycled.
Another pic with less glare


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I am glad that things are stabilising and that the remaining discus seem to be OK. The antibiotics must have wiped out a lot of beneficial bacteria. But evidently something was going wrong before that to cause the disease issues. Your maintenance regime seems good for most fishes. I am not sure about discus. I did briefly consider keeping discus myself but was put off by the thought of daily water changes and a bare bottom tank, as well as the price of the fish. I thought I would be constantly worried about them instead of enjoying them! They are lovely fish though. So, I don’t have personal experience with discus. I know they do prefer to be in groups but to me your tank seems very small for a group of 6-8 but I would take the advice of someone more knowledgeable about discus like 86 ssinit I have heard of people keeping angelfish with discus but I think it is usually not recommended as they are more aggressive and can bully and stress the discus. Prolonged stress leads to disease.

I am wondering why you have had no success with plants, there are many that are very easy to grow and don’t need CO2 or even much in the way of fertilisers. What plants have you tried? Diatoms are common at first but usually disappear on their own, though reducing the light to 6 hours per day at first will allow the plants to get established while not encouraging too much algae. Also if you plant lots of plants from the beginning rather than just a few this helps them outcompete the algae. I have seen photos of some very nice planted discus tanks, but a lot of discus keepers prefer to have their plants in pots as this facilitates the regular cleaning of the tank floor.

Anyway, I hope things go well, good idea to move the betta!

86 ssinit

Ok the tank and fish look fine.
Water quality with discus is something totally different than with other fish. Beef heart needs to be cleaned out daily. Pieces will sit under every decoration in the tank. It alone is a major reason the water needs to be cleaned. Even Stendker beef heart is dirty. Stendker has great discus. They sell there own beef heart. They say whatever to get you to buy there stuff. Just salesmanship. They say their discus are fine in 200ppm of nitrate. Than later in the same report they say more water changes are better.
Many other foods to feed discus. I feed the cera granules and freeze dried black worms (fdbw) and quality flakes. I feed at least 3 times a day. I clean my tanks twice a week. But for the first 6 months I cleaned a lot more. Both of my tanks are over 2 years old and well established. As a beginner clean water is you major step to success. Read up! Pop eye is cause by dirty water. The discus nodes are from dirty water. This same water would be fine to great to 90% of the fresh water fish most keep. The pop eye came from the rotting beef heart.

You’ve got a great looking tank now so please just change the water and those discus will grow and be healthy.

I have a thread here about starting with discus. I put this up just so people have an understanding about discus. These really are great fish! When kept correctly they will live 10yrs and can grow up to 8-9”. So much can be done with these fish. The hardest part is where you are now. New discus take time to adjust. Small discus need lots of clean water and food to grow.

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