Two dead fish...very worried

[Liz76]

I have a 20 gallon planted tank that had been doing well for 6 months. Wednesday my Betta, Benny, died from an unknown issue, then on Friday one of my Rasoboras was found dead at the bottom of the tank. My water parameters are fine. I've been doing 40% water changes every week. Two days before my Betta passed I added a Java fern, 10 ghost shrimps, and an airstone. Before those additions I had a Betta, 3 Ottos, 7 Rasboras, and 2 Nerite Snails. My Betta was very happy and healthy looking. One day after the additions he seemed sluggish and the next morning it was the same behavior and I knew he was sick because he did not want to eat. When we looked at him he did not have any swollen eyes, or swollen body and no white stuff anywhere on him. The Rasboras were acting normal in the morning, fed them some live brine shrimps and once I came home I found one dead.
Does anyone have any help or input for my situation?
P.S. I really miss my Benny

 

[haynchinook334]

Whats your filtration like?


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[BettaFishMommy]

it is possible that something came in with the shrimp or the plants. this is why it is always a good idea to do a month long quarantine (at the least) in a separate tank on new fish/inverts/plants going into your tank, unless you 100% trust the source they are coming from. did you happen to dump the water from the shrimp or plant bags into the tank? contaminated water (bacteria or parasite) could be the culprit here, especially if you purchased at a big box type store. your betta and the one rasbora may have been slightly weaker than the rest of your stock, and that is why they passed away. keep a close eye on your remaining fish, and up the water changes for a bit, to ensure their environment is as clean as possible. if additional fish pass away soon, then medication (dependent on symptoms - the wrong meds can do more harm) may be necessary.

when you say your water parameters are 'fine', what are the exact test results and what test kit (brand and type) are you using?