My 20g tank has had a bunch of mysterious deaths this week.
Ammonia=0
Nitrites = 0
Nitrates about 10/15
Ph 7
Lost this week 2 pygmy Cory's, my remaining 2 panda Cory's. One cherry shrimp, a peacock gudgeon and most surprisingly my betas who was fine the night before. The major change I made was i replaced my substrate from gravel to pool filter sand. Did cause a mini cyle that only lasted two days. Also moved my black neons out and replaced with the pygmy Cory's two weeks ago. Both a pygmy and panda cory were acting sick before they died. All the fish in tank are acting super skittish. Generally a skittish tank to begin with. Confused by deaths. Heard that a change to sand could release ammonia pockets but it is coming up as zero. Any help would be appreciated
Ammonia=0
Nitrites = 0
Nitrates about 10/15
Ph 7
Lost this week 2 pygmy Cory's, my remaining 2 panda Cory's. One cherry shrimp, a peacock gudgeon and most surprisingly my betas who was fine the night before. The major change I made was i replaced my substrate from gravel to pool filter sand. Did cause a mini cyle that only lasted two days. Also moved my black neons out and replaced with the pygmy Cory's two weeks ago. Both a pygmy and panda cory were acting sick before they died. All the fish in tank are acting super skittish. Generally a skittish tank to begin with. Confused by deaths. Heard that a change to sand could release ammonia pockets but it is coming up as zero. Any help would be appreciated