Hi all, hopefully someone can help me or give some good advise. My fish have been doing great for the last couple months, and now suddenly I've had some deaths that don't make sense. 2 guppies died yesterday (young adults), and now today a neon tetra died (juvinile). No warnings before the deaths, the fish appeared normal, then suddenly later that day found dead.
My tank a well cycled and established 15g with a 20g Whisper filter with a bio-ammonia filter. The fish do better with this filter than they did with my old filter I had months ago (a 10g Whisper with no bio-ammonia filter). Temp is regularly 75F range, pH norm 7.3, ammonia less than 0.02 ppm. The fish eat twice a day premium flakes with freeze-dried bloodworm substituted once per week. Lighting is regular time and even length. No exposure to sunlight. Community include about 10 guppies varing is breed and age, 5 neons (used to be 6), 2 platies, and a small algae eatter (about 1 inch and rarely see him). Lots of places to hide provided for the fish.
All my fish seem healthy and are eatting well. One of the female guppies just dropped a few babies yesterday. I use a liguid test kit to check the tank parmeters. I'm very confused why suddenly there are deaths since the parmeters are normal and unchanged. Plus, I know it is unlikely for a fish to drop fry if there is something wrong in the environment. Any advise would be greatly appreciated. Thanks.