Red Eye Tetra Injured?

[senda_letter]

I have a tank with a few different fish, I have been advised they are all peaceful fish. I have:
5xMale guppies
2xDanios
5xNeons
3xBlack Neons
1xBlack Widow tetra
1xpenguin tetra
1xred eye tetra
1x bristlenosed pleco

I also have another tank which at the moment just has 1 adult female and smoe baby guppies.

I noticed yesterday that the red eye tetra seemed to be bleeding around the bottom fin. I think there is also a chunk of the fin missing. I actually inherited all of the tetras and I know they have been living together and are what is left of a community that have been going for at least 2 years so they are getting on a bit. The penguin tetra seems to be quite terratorial and chases any fish that comes near him but I've never seen him do anything other than chase. He is also the largest of the fish in the tank. He particularly likes to chase the red eye tetra and I'm worried they could have had a fight and thats how he got the injury. I left it overnight and the red eye seems better now (no blood) but I wonder if I should move him to the other tank or even if I should take the penguin tetra out and put him on his own in a new tank. I have a 10L tank that has no fish in it at the moment.

I didnt want to put the red eye in the tank with the babies incase it was some sort of disease. All the fish seem to look healthy, including the red eye. I've included a photo to help, sorry about the quality but I'm not very patient when it comes to photographing a moving object. The tail fin looks like it has a chunk missing too, but it was like that when I got him/her.

 

[Corleone]

Red under the skin can be septicemia or infection. Chunks missing from fins can be just about anything - tears happen, every fish will suffer them from time to time, but it can also be finrot or just a nip (tetras tend to nip one another. Generally harmless, but does occasionally leave little notches or splits). The picture doesn't look too bad, but it's a bit fuzzy. If the fin seems to be receding, that'd be finrot, but if it doesn't seem to be changing much, it's probably just a tear. The edge of the fin might be cloudy as it grows back, which can look like finrot (it's caused a couple false alarms for me).

What size is the tank, and do you know water stats (ammonia/nitrite/nitrate particularly). Ammonia and nitrite can contribute to many infections, including those I listed. Also, I'm a bit worried that the penguin tetra is the largest fish in the tank if they've all been there for 2 years. The bristlenose should be biggest by a good margin, and a couple of the other tetra species should be comparable length but deeper bodied.

The penguin tetra's behavior is probably from being apart from a shoal. Shoaling fish kept without the security of a species group can act weird - sometimes they become shy and hide, other times they become defensive and snap at any fish that comes near them.

 

[Colin_T]

The fish in the pic is a lemon tetra and not a red eye tetra. Red eye tetras are fin nippers, lemon tetras aren’t. Red eye tetras have a silver body and big easy to see scales.
Corleone made a good point. Most tetras are schooling fish and need to be kept in groups of their own kind. When they are kept on their own, their behaviour can change quite dramatically due to the stress they are under. This can cause them to become shy and retiring, or turn into psychopaths and attack everything.
I’m not sure how big the tank is or how long it has been set up for, but if the filters are established and you have room, I would try to get the numbers of each species up to 8 or 10. This means adding more Danios, black neons, penguins & lemon tetras. I would get rid of the black widow tetra because they are fin nippers and will cause problems to the male guppies and other fish if they get excited or stressed.
If the tank is small then get rid of a couple of species of fish and increase the number of the ones you keep.
Tetras don’t eat a lot and aren’t very messy fish. So you can keep a few of them in a smallish environment as long as you monitor the water quality and do regular water changes/ gravel cleans.

As for the damaged fin, it should be fine and heal up without any help. If it starts to go red and inflamed then a bacterial infection is infecting the site. If it goes white and fluffy then fungus has gotten into the area. If this happens you will need to treat the fish with an appropriate medication. But don’t bother adding anything unless you have to.
If you increase the size of each group the fin nipping and agro behaviour should stop.

 

[senda_letter]

Thanks for the replies, in answer to most of the questions:
The water quality is fine (amonia 0, nitrites 0, nitrates <5) and I have done weekly water changes since I got the tank and I made sure I did the fishless cycle (from info on this forum) until the tank was ready to add the fish. I'm pretty sure it isnt finrot because it happened overnight and doesnt seem to have got worse or better after that. The red was there in the morning and gone by the next morning.
The pleco is only a baby, I got him about week ago as well as one of the danios. I intend to get more danios but I dont want to overstock the tank. Its a 125L Juwel tank and if my working out is correct I have room for about 1 or 2 more " of fish. As I expect the pleco and danio to grow and also one of the baby guppies may be male and therefore need adding to this tank, I didn't really want to get any more at the moment.
I was told he/she was a red eye tetra but when I was looking at other pics I did think my fish looked a bit yellow.
Ideally I would like to get rid of the penguin tetra but I dont think its fair to give it to the lfs as its so old, someone would be very dissapointed if they bought it and it died within a month, also I wasn't sure how it would cope with being moved so much.

I had thought about getting some more black widow tetras at some point, possibly to go in the other tank when the babies are a little more grown up. Everything I have read suggests they are peaceful and the one I have is certainly very peaceful. None of them seem to hide (apart from the pleco) and the penguin tetra is the only fish that has shown any signs of being even remotely agressive.
Would it be better to take the penguin tetra to the fish shop or keep him?

 

[Colin_T]

I gather you are working out how many fish you can keep by using the 1inch per gallon rule. If so forget about it because it is an outdated system. Further to that tetras & guppies are small and have very little body mass. This means you can keep a lot more of them in the same tank compared to angelfish or oscars. Hypothetically you could have 20 x 1 inch neon tetras in a 2ft tank, yet you couldn’t keep a 6 inch oscar in it.
Most shops don’t care how old a fish is as long as it is healthy. I would take the black widow and the penguin tetra (if you don’t want it) to the shop and get some more of the other fish.
In a 125litre tank you could have: 1 b/nose pleco, 5 male guppies, 6-10 danios, 6-10 neons, 6-10 black neons & 6-10 lemon tetras. Just monitor the water quality and do regular water changes and gravel cleans and that number of fish would be fine in the tank.

Don’t mix black widow tetras with guppies because they won’t do well. Other fish to avoid include red-eye, beunos aires, serpae & Columbian tetras, and tiger barbs. These fishes are all fin nippers and will damage fish with long fins like guppies, angelfish and male Siamese fighting fish.

 

[senda_letter]

Thanks for the info. Wow I didnt realise I could have that many fish in the tank. I'l defintately be following your advice. I have been wanting some more danios but just didnt think the tank would fit them.