Lost a fish and another is showing similar signs ?

[BoltonN]

Afternoon, on friday i lost the first of the pristella tetra batch that i got around 3 months ago, they spent 6 weeks in a quarantine tank (all looked good) and then was moved into the main tank where 2 other larger pristella tetras were.

When observing the tank they all seem to be behaving 'normally' they are shoaling quite well and don't have any torn fins or anything. However, one of the fish a couple of weeks ago started showing some black markings which looked bruise like. It started to swim away from the rest and stayed in the plants. Throughout the day no noticeable chasing went on, however when they have been fed one of the larger original tetras seems to stay around the top of the tank and actively chase off any other fish that swim near it. This happens for around 30 mins after feeding and then things return to normal.

This fish that had been showing the black marks died on friday (pics below). Now since then another of the fish has started to show the exact same markings and i'm just worrying that it will go the same way as the other. Does anyone have any ideas as to what may be causing this or anything i can do to stop it ? Does it definitely seem as if it is bullying that is causing this or could it be something else?

Parameters = 0 for ammonia and nitrites, nitrate 5ppm, pH of 6.8, Temp 24.5, gh 4gdh and kh 2.

[Stephen]

Does anyone have any ideas as to what may be causing this or anything i can do to stop it ? Does it definitely seem as if it is bullying that is causing this or could it be something else?

Parameters = 0 for ammonia and nitrites, nitrate 5ppm, pH of 6.8, Temp 24.5, gh 4gdh and kh 2.

You're parameters are spot on for Pristella x-ray tetras, virtually perfect.
Remind us of the other fish you have in the same aquarium please.

[plankton]

Sorry for your losses.
X-rays are normally pretty hardy.
I think there's something internal going on there. The last pic with the black at the front could well have liver and kidney problems.
I'd treat for internal parasites and see what happens.

[FishyMcFishFace]

Must be horrible when this happens, hope you get to the bottom of it.

[BoltonN]

@Stephen The tank includes: 11x pristella tetra, 1x albino cory, 1x runmy nose, 2x assassin snails and 5x otocinclus. Currently in the quarantine tank are 7x red phantom tetras and 6x panda cory. This will be the full stock of the tank - the panda cory are hopefully going to shoal with the lone albino (he's around 8 years old and is the last remaining cory of a group of 6 albinos - got pandas as they seem a tad smaller when fully grown and are similar in colour to the albino so will hopefully help the albino feel a part of a shoal again. In regards to the rummy should never really have been put in this tank (120l and more cube than long) but is again around 8/9 years old and has spent his life in here so felt a bit counter intuitive to try to rehome such an old fish just for the sake of having a more suitable tank when it has lived a long life in this tank.

@plankton Thankyou, it's certainly worth a try with these others that are showing dark marks, i was unsure if they were bruises or something more. I will try to get some better pictures of the current ones with these markings, that one in the last picture is the same fish that passed away sadly.

@FishyMcFishFace It sure is annoying but hopefully once it's sorted these fish should thrive ... fingers crossed

[BoltonN]

Some more images of the currently affected fish. 1 looks quite bad - all of its sides have these bruise like markings and seems to be swimming lobsided/irregular, the other has a slight mark on the 'tail end' of its body but is swimming perfectly fine.

[BoltonN]

Yet another of the pristella tetras is showing the exact same markings, however when trying to give it a salt bath as it looked bloated i noticed that the scales of the fish had started to pine cone. Does this mean that dropsy is occurring ?

Also the fish that showed signs earlier has now all but lost its ability to swim, it just seems to float around the tank in the flow. It has been moved to a hospital tank with just a heater, and air stone. I've tried to really limit water movement by withholding a filter as the fish was just getting battered around by any even a small sponge one. I am changing the water twice a day, once in the morning and once in the evening. It has some salt added but is mainly being treated with a swim bladder treatment.

I really am stuck with what's best to do for these fish, i've been monitoring the main tanks water almost daily and just seen constant 0 ammo, 0 nitrite and between 0 and 10 nitrate depending on how long after the water changes. pH has stayed around 6.8 and gh is 4 and kh 2. Temp is 24.5. I just feel like i'm losing fish after fish, 1 has gone so far and these two seem on their last legs.

edit: Should also add i treated the main tank with melafix to try and help if it was a bacterial infection however i don't know if this wasn't strong enough or just incorrect

[plankton]

Some tetras do darken with age, but yours don't look big enough to be around 5-7 years old.....unless you have the temperature very high, which you don't.
Treat with Esha 2000 which is a broad-spectrum med.
It sounds as though this is going to be one of those frustrating problems where we don't actually find out what's causing the water retention (which is what "dropsy" actually is) unless by accident.

[BoltonN]

Some tetras do darken with age, but yours don't look big enough to be around 5-7 years old.....unless you have the temperature very high, which you don't.
Treat with Esha 2000 which is a broad-spectrum med.
It sounds as though this is going to be one of those frustrating problems where we don't actually find out what's causing the water retention (which is what "dropsy" actually is) unless by accident.

I know it's not looking promising , the tetras affected are probably under or just over a year old they're not old at all, there are 2 in there that are around 7-8 years old but they're easily distinguishable they're practically double the size. I'll get some esha 200, just out of curiosity is there any other medications that you'd get stocked just in case needed. Currently only have pimafix, melafix, api aquarium salt and an anti fin rot one (had a new red phantom which is currently still in its first 6 weeks of quarantine have fin rot and a glazed over eye, the fin rot has cleared and the eye seems to be on the up). Thankyou so much for your help once again