Is my fish sick?! Tail hanging low

[SpaceUnicorn]

Hi! Thanks in advance for your help!

• Chemical and temp measurements - all good
• Tank size - 65 gallons
• Fish in question: long finned glofish tetra, we’ve had for about 6 months
• Last water change - last Saturday morning (4 days)
• Last addition of new fish - algae eater added 3 weeks ago
• Fish in tank: 2 angel fish, red finned shark, algae eaters, moonlight gourami, panda catfish, glofish tetras, glofish Dario, glow fish barbs, sailfin balloon fish, and pleco.

Tonight we noticed that Ralph was swimming randomly and very jerky with his tail hanging down low. And as soon as he stops moving, quick to sink. It almost as if a weight is tied to his tail and pulling him down.
I have videos but need to upload to YouTube to post here, it looks like I can’t just attach one - will follow up shortly.

 

[SpaceUnicorn]

Hi! Thanks in advance for your help!

• Chemical and temp measurements - all good
• Tank size - 65 gallons
• Fish in question: long finned glofish tetra, we’ve had for about 6 months
• Last water change - last Saturday morning (4 days)
• Last addition of new fish - algae eater added 3 weeks ago
• Fish in tank: 2 angel fish, red finned shark, algae eaters, moonlight gourami, panda catfish, glofish tetras, glofish Dario, glow fish barbs, sailfin balloon fish, and pleco.

Tonight we noticed that Ralph was swimming randomly and very jerky with his tail hanging down low. And as soon as he stops moving, quick to sink. It almost as if a weight is tied to his tail and pulling him down.
I have videos but need to upload to YouTube to post here, it looks like I can’t just attach one - will follow up shortly.
View attachment 131241View attachment 131242

Hi! Thanks in advance for your help!

• Chemical and temp measurements - all good
• Tank size - 65 gallons
• Fish in question: long finned glofish tetra, we’ve had for about 6 months
• Last water change - last Saturday morning (4 days)
• Last addition of new fish - algae eater added 3 weeks ago
• Fish in tank: 2 angel fish, red finned shark, algae eaters, moonlight gourami, panda catfish, glofish tetras, glofish Dario, glow fish barbs, sailfin balloon fish, and pleco.

Tonight we noticed that Ralph was swimming randomly and very jerky with his tail hanging down low. And as soon as he stops moving, quick to sink. It almost as if a weight is tied to his tail and pulling him down.
I have videos but need to upload to YouTube to post here, it looks like I can’t just attach one - will follow up shortly.
View attachment 131241View attachment 131242

 

[Colin_T]

The fish has problems with its swim bladder.

The fish sinks as soon as it stops swimming. There is no cure. Normally these fish get eaten, You can leave it be or euthanise it. They burn up heaps of energy and suffer a bit of stress if you leave them, because they spend all their time and energy trying to swim with the others.

I normally euthanise them when it happens.