First dead fish


New Member
Aug 11, 2020
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This morning I woke up to see a dead guppy in one of my plants. He was fine last night and there didn’t seem to be anything up with him. He has been in my tank since Sunday. It looked like his fin was torn/eaten. I have heard about fin rot but not sure if this can happen overnight?

This afternoon I found one of my neon tetras upside down dead. His eyes looked like they were bulging slightly. The tetras have been in my tank about two weeks.

Are these two linked? What could be causing my fish to die?

The tank has been running for a while and had 4 Guppies, 10 Neon Tetras, 2 Platies and 2 Amano shrimp. It’s 120 litres (approx 30 usg) and I’ve been doing regular water changes.

The readings are Ammonia 0ppm, Nitrite 0ppm, Nitrate 0-2ppm. The PH is 7.0 and the temperature is 26c (79f).

AdoraBelle Dearheart

Fish Aficionado
Tank of the Month!
Jul 22, 2020
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I'm sorry about your fish :( Losses are always hard.

When you say the tank has been running for a while, how long is a while?
When you clean the filter, how do you do it?

The water parameters sound great, but since you've added new fish recently, it's possible there was an ammonia spike perhaps... do you have live plants in there that might have taken up the ammonia before you did a water test?

If we rule out all of these things, then it's possible that the new fish bought in a disease from the store, it's not uncommon for them to be exposed to all kinds of illnesses during shipping, then at the store since most have a shared water system. It would be a good idea to get a quarantine tank for future stock, it's much easier to monitor and treat new fish in a ten gallon quarantine tank than it is to treat your main display tank when something goes wrong. I'm currently treating two main tanks for worms that likely came in through guppies that I didn't medicate in quarantine, and trust me, it costs a lot more money in meds to medicate 76 gallons of water instead of 10 :oops: And some of my plants suffered from the treatment, which is not only disappointing since I love my plants, but means they've shed a lot of plant debris which could easily cause an ammonia spike without cleaning them up.

I'm gonna be a boring old person banging on about quarantining, sorry guys! But want people to learn from my mistakes rather than the hard way.


Fish Herder
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Jul 14, 2020
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Washington State, USA
Also, do you know the gh and kh of your tank and tap water? When guppies are kept in softer water the will be more likely to contract illnesses. As far as I know, guppies need hard water and neons need soft water.