Something is wrong with this fish

[rebe]

I first noticed that something was wrong on the evening before I left to go on my trip. That was the 22nd of October. One of my hengels rasboras seemed less active and paler than the others. Not by a lot, but to me it was noticeable. I got my mum to check the temperature and see if the fish were okay each day that I was away. I got her to feed them once in the middle of my time away, bug bites that I'd crushed and set aside to avoid over feeding.

I got back yesterday and it's now very clear to me that something is going wrong with this fish. One of them seems to have trouble staying in place and it spends a lot of time swimming at a 45 degree angle. It seems very pale now in comparison to the other fish. I fed the rasboras yesterday and today, and I don't think I saw this one eat. I haven't been able to monitor it's poop, the fish are very small and quick. They don't seem to poop a lot. Also, it might not have much to poop since they were all mainly fasting while I was away. I have no experience with fish disease at all, but my best guess is an issue with it's swim bladder?

I don't see it rubbing or scratching against anything, and it still follows the group around.
13 in the group, in a planted 29 gallon tank. The water quality and temperature are perfect as always. Normally fed oase organix micro granules, oase organix flakes, or fluval bug bites micro granules. I normally change around 50% of the water once a week, and did a small water change before I left for that trip.

The only changes I've noticed in the last few weeks are mulm building up, brown algae spots on the glass near the substrate and a small population of seed shrimp in the tank. The seed shrimp showed up with the mulm, so I assume there is a connection between the two.

Videos I took yesterday, edited together:

A short video that I took an hour ago:

 

[GaryE]

Swim bladder isn't a disease, but a symptom of many diseases. The 2 bladders are fed by intestinal gas to maintain balance, and when something goes wrong in the digestive system, the swim bladder malfunctions. What can go wrong is vast - everything from constipation to cancer. We can't see into the fish to give a real answer, and all we can do is guess.
On the off chance the problem is communicable, it's best to isolate the fish. Very few of us have fully cycled aquariums at the ready for use as hospitals though. I'm afraid with that fish, the chances are not good. There's always a store willing to sell you a remedy, maybe even sincerely, but no commercial remedies (notice I don't say medications) will work on what I see in your vid.
The tank looks like a great environment, and sometimes, in the best of places, things go wrong and bodies break down.

 

[AdoraBelle Dearheart]

Agreed with the above, and while not many people have a second tank to use as an emergency hospital or QT tank at the ready, you could use something like a breeder box to isolate the sick one merely to prevent the others from consuming the body when it passes away. It might not have anything communicable, but it's better to be safe than sorry.

Given that this isn't a water quality issue, and certain tank-wide diseases aren't likely since it isn't a new group of fish, and it's one out of an otherwise healthy looking group in a great looking tank, I'm also leaning towards something internal being wrong with this fish, and it's reached a bad stage that the fish is unlikely to recover from. I would probably euthanise at this point, the fish is very, very unlikely to recover, is struggling and stressed (paleness, visible difficulties swimming) and I don't like to see animals suffer if we can help. But there aren't really meds for generic "fish is dying, cause unknown" that won't harm more than they help, and I definitely wouldn't introduce a random med in a last ditch attempt to try to save this one fish, when that's much more likely to cause harm to the remainder of the group.

But if you're unable or unwilling to euthanise, and can't isolate the fish to a hospital tank, then a plastic breeder box (I've used net ones in a pinch, but it's still possible for the others to nip bites from the body through a net) attached to the main tank to prevent the other fish from bullying the sickly one and from eating the body when it does pass would be a potential solution. Sorry I don't have better news though, it's a beautiful tank, and the rest of the fish look great. Sometimes it's just bad luck, no matter what we do.

 

[rebe]

Thank you for your replies @GaryE and @AdoraBelle Dearheart .
I don't have a fully cycled hospital tank unfortunately or a breeder box. The fish isn't showing any signs of improvement, I'd almost say it's having a harder time swimming after the others. So I think it seems like the kindest option is to euthanize this fish?

Euthanize a fish in a PAINLESS way

It is a very sad and tough moment to deal with, but you will maybe have to do it, one day or another... Here is how I proceed using essential clove oil which is according to me the only painless way to make your fish pass away as clove oil is an effective anaesthetic. Good luck. As difficult...

www.fishforums.net

This is the guide I'm planning to follow, is there anything I should do differently? I've heard of people using alcohol to dilute the clove oil, but the only alcohol I have is hand sanitiser. I have a small plastic tank, but would the clove oil contaminate it for future use?

 

[Essjay]

Clove oil will contaminate it. It leaves an oily residue and it smells - in my opinion it smells horrible. I always use rubber gloves when using it as it stays on my skin for hours. I would use something you won't want to use again except for euthanising fish over the years - I have an old margarine/butter-substitute tub for use with clove oil when I have to do this.

 

[rebe]

Clove oil will contaminate it. It leaves an oily residue and it smells - in my opinion it smells horrible. I always use rubber gloves when using it as it stays on my skin for hours. I would use something you won't want to use again except for euthanising fish over the years - I have an old margarine/butter-substitute tub for use with clove oil when I have to do this.

Thanks @Essjay . I'll use a smaller plastic container I have, and keep it in the shed when I'm finished. Hopefully to never use it again!

 

[GaryE]

I use glass jars, cleaned up after use. I'm afraid it's the humane option, as fish in that state don't get better.

 

[AdoraBelle Dearheart]

Thanks @Essjay . I'll use a smaller plastic container I have, and keep it in the shed when I'm finished. Hopefully to never use it again!

I'm sorry that you've had to join the ranks of us having to use this method, but sometimes it really is the kindest option to prevent further suffering.

I also use old, cleaned out empty fish food containers or margarine tubs for this kind of thing, kept in a kit with clove oil in a box separate from all other fish stuff, and also hate the residue it leaves, so use gloves when I have to do this. Alcohol isn't essential at all.

The trick to using clove oil is to use only a few drops to begin with, mixed as best as possible in warm water and added to the container of tank water. A little of the clove oil when passing over the fishe's gills sends the fish to sleep, it's also used to sedate fish for operations, when the amount used is enough to send the fish to sleep, but not kill it, then the fish is revived when placed in water without oil, usually under a filter output so fresh clean water is washing over the gills to clean away the oil and revive the fish. You can see people use this method to try surgery on expensive fish like arowana.

When using clove oil to euthanise, how much to use will depend on the size of fish and quantity of water you're using. For a small tetra in something like a margarine container, a few drops should be enough. Swirl it into the container of water taken from the main tank, then add the fish to be euthanised and give it a couple of minutes, watching the fish. When fin and gill movements slow, it's a sign the fish is sedated. Can use a gloved finger to gently move the fish and check that it appears to be asleep, and doesn't react to being nudged. Add a few more drops if the fish is still responding/not going into a sedated state.

Once you're confident the fish is sedated, then add an overdose of clove oil mixed with the warm water. 10 plus drops is likely enough for a small tetra, but opt for more if you're concerned, or with a larger fish. After the overdose of clove oil is when some people add a high concentration alcohol like vodka, to be absolutely sure the fish has passed away, but it's not essential. Clove oil alone when given in the high concentration is enough to stop the heart. Once you think the fish has passed away, keep it in the container of clove oil for 30 minutes or so to be absolutely sure, before disposing via burial or general waste disposal, never flushed or disposed of in waterways.

The few fish I've had to do this with, I haven't experienced a problem, but the ones I've heard about seem to have been when someone had added a fish directly to a container that already has a high concentration of clove oil. Too much, too fast, and the fish panicked. But introducing it gradually means it sends the fish peacefully to sleep. Like when a vet euthanises a mammal, they give a dose of something to sedate the animal and put it to sleep, before giving the overdose that stops the heart and breathing. Clove oil is the method we've found most closely able to replicate that in the fishkeeping hobby.