hello, i’m so sad. i went to pass my fish tank it’s 2:31 am so it’s the middle of the night. earlier around 6 pm i did a water change and added this new hide i got from petsmart. as i went to look i noticed one of my guppies had a huge chunk missing from her tail! my only guess is the new house because nothing else i have in this tank is bad. it’s a 20 gallon tank with 8 female guppies and 4 nerite snails. i his tank has been up and running for a year almost 2 at this point. i’m not sure what happened. how to i make sure this guppy doesn’t pass. these fish are really sentimental so i feel just terrible that one of them is injuried. any advice is helpful. i already added salt. just now.