Newly subscribed and looking for some help.
1. Glowlight tetras and neon tetras have been getting sick over the past 3 months about 1 fish per month. 1 neon tetra head cotton mouth/ white growths. 3 glowlights experienced lethargic behavior, seemed to be struggling to stay afloat but could use side fins still when provoked, were mostly swimming almost in a vertical poses (either head up or down) and really just moving with the current, were experiencing almost violent neck spasms as if glancing over their shoulder (only looking to the right), were gasping rapidly, and their bellies had turned almost solid white. See photo.
2. Ammonia, nitrate, and nitrite levels are at 0. Ph is 6.8. General hardness is a little higher than I'd like, but it's at 100 ppm
. Temp is 78.3 F.
3. Tank is 30 gallons, been running for a couple years, but did a 50% water change acouple months ago then weekly 25% for a few weeks to resolve serious water conditions. Ph had swung from very acidic to alkaline due to issues with the sand substrate.
4. Filter is Marineland Penguin Bio-wheel 350
5. Have 2 Cory catfish, 1 algae eater, 8 glowlight and 6 neon tetras.
6. Did a 50% water change a couple months ago due to spiking ph from substrate and switched to rocks. Vacuum the gravel at least once a week (except the past week due to family emergencies) and a 10-20% water change every other week.
7. Have had the affected fish for 4 months, others are 6-8 months.
8. We added some new plants from petco a couple months ago. The snail free ones in the tubes and a few masimo balls (sp?). We also just added a couple of Halloween decorations last week.
9. Fluval bug bites color enhancing formula and freeze dried blood worms
Any insight would be appreciated. I assume it's NTD but want to be sure.
I euthanized the fish after the photo as the spasms were on day 3 and it's no longer trying to swim. I didn't want it to continue suffering...
Thanks in advance,