Guppy mortality

[vavvet]

Dear all,


We have a 90l aquarium with guppies, tetras and corys. About an year ago we had an ammonia spike and since then we have struggled with our fish health...Itch, dropsy, sudden death etc... 2 days ago I noticed that one guppy was lethargic and had lost the colour of the second half of his body...colour and movement... Today I have another fellow just like that but this one has dropsy as well. For me it seems some type of necrosis that progresses very quickly but I am really lost at this stage...Does any of you have a clue?
Water quality seems fine.

We really appreciate all the help that we can get!

 

[Delapool]

Any ideas on ph, kh and gh?

Live bearers I’ve found do a little better in harder water (for me). Large water changes, big tank rescapes and perhaps weak stock have also been issues.

 

[vavvet]

Dear Delapool,


Thanks for your post.


As per yesterday:


NO3 - 10
NO2 - 0
gH - 7

kH - 6
pH - 6.8
Cl2- 0


Thanks.

 

[vavvet]

And...a better picture now attached.


Thanks!

 

[Delapool]

On mine that has been bacterial infections where colour loss and several fish at once. A weak fish can be a one-off here. Also could be parasite infections but they are rare here.