2 dead fish, a dead crab and a color changing male guppy :/

[kirsty13]

Hey guys,
Really worried about my tank set up and my remaining fish :/ set the tank up 2 months ago, the first group of fish I put in were 9 neon's, 4 platys and 2 other orange fish. After 3 weeks in the tank and 15 new baby platys I put in a crab (son was desperate for one ) and 4 guppy's last week. Yesterday I came home to 2 dead guppy's, a male and female, and a crab that was acting 'dead'. My remaining male and female guppy's are acting strange - lying on the bottom of the tank or floating at the surface barely moving their fins. Now my male guppy as developed huge black eyes and his face has changed from his usual blue/silver color to black. Now the crab is dead - definitely not acting! What am I doing wrong? Why are they dying and transforming??

 

[54seaweed]

Sorry to here about your fish and crab , first thing I am going to ask is this.
What size tank do you have ?

how often do you do water changes ?

have you checked your parameters ? what are they ?

depending the size of the tank 34 fish can be a lot . you can have a overloaded tank causing lack of oxygen , ammonia poisoning could be another thing to look at . your bio load may not be be established enough to handle that many fish . there could be many factors to this . once you post your parameters tank size . we can get a better idea of what's going on .

 

[kirsty13]

The tank is 3foot long by 1 and a half feet tall, there's a Fluval4u filter in it that was already in my dad's 4ft aquarium for 9 months before it was put in mine. I used terra test strips to test the water and it says everything is within the ok range. I half change the water last night after I removed the dead fish, they had been there all day :/ previous to yesterday the water was changed last friday, it was the first time since I put the fish in as the plattys had babies overnight so they weren't removed from the tank and I was scared in case I killed a few :/ I did keep checking the water , the nitrates were high we than normal last Friday which is why I did the water change, all the tests are fine now. My other fish in the tank seem happy enough are all eating, the babies are even growing, it's just the guppies and the crab that seems to have been affected.