Neon Tetra(s) acting strangely and floating on top of tank

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FightingFalcon

Aquarium Advice Newbie
Joined
Dec 13, 2017
Messages
4
Location
Arizona, United States
My Neon Tetras are swimming strangely. I just fed them, and they ate normally. Then they all started diving towards the bottom of the tank, but floating upwards, like their tails are buoyant, and the mannerism of swimming is very jerky. I have one in particular who will rest sideways on the top of the tank, just floating there, like he is dead.
I'm wondering if I overfed them (but I don't think I gave them any more than normal, and they've eaten fine before with no issues), or if it could be a swim bladder problem (affecting all of them seems a bit odd though), or if it could even be the Neon Tetra Disease.

I just had my tank water tested today. The guy at Petco didn't have a water chart sheet to give me, but if I remember correctly the ammonia level was around 0, and either the nitrites or nitrates were slightly high but still within normal range. The temperature of the tank is room temperature and never changes from a solid 78 degrees Fahrenheit. The pH is about as soft as it could possibly be, I just use my drinking water for them (I had originally used a "special" water purchased from the pet store for them, but upon discovering the Neons liked a softer pH I slowly switched it over to my regular drinking water that runs through a reverse osmosis system, free from any chlorine, contaminants, etc.)

The tank itself is a 5.5 gallon Aqueon MiniBow LED Desktop Fish Aquarium Kit, with an Aqueon MiniBow filter (the filter cartridge was changed about 3 weeks ago). I'd set up the tank about 8 months ago, with 10 Neon Tetras and 1 Bristlenose (I think) Pleco. I know that my tank is overstocked but the fish seem to be doing fine, and all have been completely healthy, and I intend on getting a 10 gallon tank of the same brand and style in a few weeks. [On a side note, does anyone have any advice on transferring the Neon Tetras and Pleco to the new tank without killing them or severely stressing them? I was thinking about putting them in a *clean* bucket with their old tank water while transferring the décor and rocks to the new tank then filling it with some clean water and then putting them in there with their old water]

I changed the water two days ago, removing about 1/5 of the tank's water (like usual) and replacing it with the same water I always use. I haven't vacuumed the gravel yet as my gravel vacuum broke since last time I cleaned the tank (about 3 or 4 weeks ago).
Nothing new has been added to the tank, apart from the water, they've had all their plants (fake, except 3 moss balls) since they were put in the tank.
I feed them Aqueon Tropical Flakes, about a small pinch (plenty for them all), roughly every other day, about an hour before I turn off their lights.

I had an algae problem with a sudden explosion of both green and brown algae on my carbon filter cartridge, and removed the cartridge (two days ago), rinsed it off under regular sink water and thus removing the algae, shook it off, and then put it back in the filter. I also have some green algae growing under/in the rocks, and what appears to be black specks along the bottom. I notice the black specks when I think it's about time to vacuum the gravel (and this black-like substance grows on the fake plants, making it extremely noticeable. This has seemed normal though, for the past 8 months or so, and I talked to my LFS who told me that it was "just time to clean the tank".

Just a side note is that today I got two Green Tiger Barbs to put in one of my other tanks (that hasn't had any fish in it, just plants). I can't see how this would affect them, because they aren't in the same tank (and never will be), but I figured it was worth a mention. The two tanks are on the same table side by side with a fake tree separating the two. Is it possible that the Neons saw the Barbs and started freaking out or something?



Oh and they seem completely normal, their coloring is bright and healthy like usual, scales are all smooth and shiny, they seem healthy apart from the "darting" like problem.

Any advice or thoughts are greatly appreciated. Thank you!!
 
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Do you feed them flake food? When I fed my neons this, they found it hard to swim down because they were getting too much air in their stomachs! I now feed micro pellets that sink and they are fine
 
I feed them flakes. Originally I tried feeding them Hikari Micro Pellets but they refused to eat them, so I went with flakes instead.

Also, they're back to normal today.

Thanks!
 
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