Fin Rot?

[Puddles92]

Tank size:25l
pH:6.5
ammonia:0
nitrite:0
nitrate:10
kH:don't know
gH:don't know
tank temp:25

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Male guppy purchased 2 days ago has a small rectangular chunk out of his tail fin. The edges of his tail look white but not sure of this is his normal colouring. He has a couple of thin red streaks in his tail as well but again don't know if this is normal. He is behaving normally as far as I can tell. Not sure if my zebra danio has taken a chunk out of him though.

Volume and Frequency of water changes:

I change 10l every week but before I added the new fish it went 2 weeks without a change as we were on holiday and a friend was looking after them.

Chemical Additives or Media in your tank:

Nothing added to the water until I noticed the damage when I changed the water and then added stress coat to try and heal the tail.


Tank inhabitants:

1 male zebra danio and 5 male guppies

Recent additions to your tank (living or decoration):

5 male guppies added 2 days ago

Exposure to chemicals:

None apart from the stress coat added once the damage was noticed

Digital photo (include if possible):
Will try but he moves so quickly is hard to get anon blurry pic.

My zebra danios top fin is also looking pale but again never looked that closely a this fins so not sure if this is just his colouring or not.

 

[phoenixgsd]

unfortunatly the zebra danio is not suitable for your tank, they are fast swimmers and need much bigger tanks so is certainly not happy in there they need larger groups too, i wouldnt be surprised if he took a snip out of your guppys tail

 

[Puddles92]

He was recommended by the pet shop as the first fish to put in the tank. We did have 2 but 1 managed to jump out. He seems pretty happy and has grown a lot since we got him last month. Should I see if the shop will take him back or just leave him?

 

[maninahat]

The shop nearly always take back the fish - though don't expect a refund. I recommend you take him back, especially as zebra danios prefer to be in groups, and there is no where enough room for one danio, let alone an entire shoal.

When I first got a tank, my LFS recommended I put in Giant Danios - into a 23l tank! When I finally learnt my mistake, I returned them all.

25l isn't enough space for most fish. It's perfect for a betta, a few otos, or maybe just invertabrates, but not much else. I've tried a school of galaxy rasbora, but didn't have much success (very shy unless more social, peaceful fish are in the tank too - but again, 25 l is too small for most fish).