Thoughts on recent ghost shrimp death issues (and mildly lethargic nerite)
I have a 2 month old Fluval Spec III (2.6 gal) with three nice clumps of sword ferns and one taller wisteria. I have some loose java moss stuffed into a cholla log, and then two marimo moss balls in there. Inhabitants are one male betta, one striped nerite snail, and 2 ghost shrimp.
I fill my tank with my public tap water, conditioned with Prime.
I do 40%-50% water changes every week. I have not yet taken the filter/media out to clean it, per the instructions on the tank. Water is tested each week with Tetra 6 in 1 strips and it has remained constantly spot on as far as no chlorine or ammonia, safe nitrite/nitrate, and safe pH. My water is very hard and it does show up as the hardest result possible on the strip.
Because it is a Betta tank, I have done the "Fluval Spec mod" of putting a foam filter piece over the filter outlet so it doesn't cause the betta stress with forceful water flow.
First month of the tank, the betta was a bit sluggish and shy, but the shrimp were going everywhere...flying up to grab the betta pellet food, investigating all over, etc. The snail cruised around really "fast", too. This last 3 weeks, the betta has gotten more and more active and really looks happy. The snail has seemed to have slowed down, staying still a lot of the time. She has been laying white eggs around, so maybe that's a sign she is healthy. At the same time, one of the shrimp turned opaque white and died. I replaced it a few days later. Then the other original shrimp got white and sluggish and died. Today, about a week later, the last remaining one, the "new" shrimp ,is white and sluggish and on his last legs.
I am confused about what could have changed.
I did recently reduce the hours of the LED (factory) tank lighting from 14 hours to 6 hours since I was having algae issues on my plants and the glass. It has improved the algae on the glass a lot, but the plants still have a fuzz of green on them. I scrape the sides each week when cleaning, regardless. I would be shocked is less light is killing the shrimp though? Plus, the tank gets decent indirect sunlight each day.
Is the hardness of the water an issue? But then why would the shrimp do so well for a month and now even new shrimp are dying in a week?
One theory which I don't think is a very good one is that the betta is now much more active and aggressive, and he eats all the food I add pretty quickly. Originally, he would just lay around and the food would float for some time so that the shrimp could swim up and and grab one each to snack on.My impression is that shrimp are pretty scavenger-y and they'd likely find all the food they need down in the gravel and in the algae/moss balls, etc.
I hate to keep replacing the ghost shrimp just to have them die in a week or two over and over. Also tempted to try the fancier blue/red/striped shrimp, but at $7 a pop, I'd be more annoyed if they are dying so quickly.