Fish Turning Blacker

[Greenman]

Hi all
first off thanks for all the info i have got from this site , has been a big help
ok i got a tank 2nd hand had it for a week and put some fish in it (i did not know fishless cycle then)
Think they are blood fin tetra.They have been doing good .
but over the last few days some of the fish have got blacker. the edge of there tail fin the big fin on there under side and one his top fin.
hear is a pic hope you can see it.


is this Amonia burn and them healing?
i do not have a water test kit i hoe to get one today is there any thing eles i need to treet the fish ?

Thanks for any help

Adrian

 

[Greenman]

The fish seem to have got angre to day, some seem to be courting. they have ust been picking on one fish and damaged his top fin.

 

[flash22]

imo its nothing to worry about both my black skirt tetras and honey gouramis have got lot darker and gained there colours (where nearly all silver when i got them. iirc there food/diet has a lot to do with it