Mystery Kuhli Loach Illness

[Nyxin]

Hi, this is my first-time posting to any kind of website like this. And although I’m nervous I’m facing a strange predicament. I have a 3 year old 10 gallon tank. It’s a black water style tank with botanicals, mopani wood, and a variety of plants. I have one male betta, a handful of cherry shrimp, some bladder snails, and 6 kuhli loaches. Everyone in the tank is fine except for my loaches. They’ve been displaying strange symptoms; swimming upside down, heavy breathing, and erratic movements. On top of that I’ve noticed strange bright red waste (I have not feed any bloodworms or other foods which would affect their stool color). There is no sign of life though which makes me want to rule out parasites on top of the fact that I haven’t seen any worms coming from their rear ends.
The tank has soft water, zero ammonia, 0 nitrates, and zero nitrites.
I would appreciate any advice I’m at my wits end on what could be affecting them.

 

[committeadmare]

I seem to remember one of the popular brands...maybe hikari? ...produce weird poop like that. It could be unrelated.

For the loaches, do you have a hang on back filter or something to create water agitation and add air? I wonder if the plants on the surface have been growing over and are starting to hinder oxygen exchange with the air.

 

[Nyxin]

I seem to remember one of the popular brands...maybe hikari? ...produce weird poop like that. It could be unrelated.

For the loaches, do you have a hang on back filter or something to create water agitation and add air? I wonder if the plants on the surface have been growing over and are starting to hinder oxygen exchange with the air.

Hi, thank you so much for responding!
I feed the tank the following foods,
- Fluval Bug Bites
- Betta Pro Shrimp Patties
- New Life Spectrum Betta Food
- Aqueon Shrimp Pellets
I have a sponge filter going to produce low amounts of water agitation as not to irritate my betta. I'll definitely test my dissolved oxygen levels and remove some floaters though.