Neon Tetra: Sick or Normal Behaviour?

[MrDibbs]

Hello everyone,

I'm a new aquarist. I don't have the readings of my water on hand, but my local aquarium shopkeeper told me everything is in tip top shape after taking a reading before I started adding fish.

Two days ago I purchased 6 Neon Tetras and 1 Sewellia Lineolata. My question is in regards to the behaviour of one of the tetras.

For the first day they all schooled together (btw, schooled and shoaled, are those synonyms?) but by the end of the first day I noticed that one tetra (the smallest one) was hanging out alone in the back/ bottom/ corner of the tank. This was also the first one who ventured to the surface for food at the first feeding (idk if that is relevant or not). The rest (other 5) of the tetras do seem to be hanging out mostly together, although they do spread out around the tank, some are nipping at each other, they school for a bit then spread out, a diversity of behaviours. These 5 all get together when I drop food in.

Two days later, I have noticed that the small one's isolation behaviour continues, and in fact it (she?) is becoming rather territorial and chases the other fish away that come near her corner.

Today is what has motivated me to question the group: yesterday and this morning the small one has not eaten. I can't determine if this is because she is sick (and also why she is on her own) or if she just hates the other fish and doesn't want to abandon her special corner of the tank by going to the surface to feed. Today she schooled with the other fish for a very brief period when I tapped on the glass (to provoke some fright response) and she quickly joined the others for just a few seconds, I guess because she was scared, so I suppose this is a good/ normal behavioural response?

I do not notice any other irregular behaviours or signs of illness. No white spots, no bumps, swimming is normal, but a bit lethargic when she hangs around her corner (however when chasing the other fish away she is agile and fast). If I HAD to say something, I would say that her body/ spine are curving just a tiny bit, although this might be me stretching to explain the situation. In her corner she does seem to stick close to the glass, but not bumping into it or anything like that.

I would like to know if anyone has experience differentiating between this being a sign of illness or if this is normal behaviour. Any other questions, please let me know. This is my first post. I have a 60L tank (15 gallon) with medium to light level of planting and everything honestly seems to be in good order except this one fish!!

Thanks in advance.

 

[MrDibbs]

Also, I have posted this "thread" in the Freshwater Forum. How would one create a new forum, if possible, just to know for the future? I am new and maybe this is not the flow of things, but I do know Neon Tetras are quite popular, so maybe this should be a forum on its own, or a Tetra forum or something? Thanks.

 

[OrionGirl]

Sounds like normal behavior.

Schooling and shoaling don't mean the same thing...schooling tends to be 'all doing the same thing at the same time, move as a group' while shoaling is being in the same general location, move along together but not at the same time'. Think geese flying in formation (schooling) versus puppies playing (shoaling). Neons have been pond reared for so long that they seldom have good schooling behavior outside of a fright response.

Users can't create new forums. Really, there isn't enough traffic here anymore to warrant breaking this out from general FW.

 

[ustabefast]

The smallest outlier one is unlikely to survive.
Neons are not the hardiest of fish to begin with and this one appears to be of low genetic quality.
If the other 5 are fine and your water parameters are good, no problem, but if this group is from a sketchy source they could die off one after another over time.
Neons are cheap but often inbred.

 

[MrDibbs]

Thanks for your responses. So I took a closer look at the tetra and I was able to separate her from the rest of them and I could confirm her spine was indeed pretty crooked, I would say two 10/ 15 degree bends in it. Also, her abdomen was inverted and not protruding at all like the other ones. All in all, she didn't look like a healthy fish and combine that with the fact she was not eating at all in three days didn't bode well. I spoke with the local aquarium store and he said he was pretty sure she is sick and it was best to put her out of her misery. So I did For the time being, the other tetras are doing really well and I would even say they are more relaxed with her out of the tank.

It's weird how animals behave and do things we might not understand. For example this tetra was chasing away the other fish when they came near her. Maybe she knew she is sick and wanted to make sure they didn't get it too? I don't know, just trying to understand.

Thanks for both your comments. I guess because they are not exactly valuable fish and I am just getting the tank set up still, I thought it was better not to risk any disease in there. I am going to wait another 2 or 3 weeks before I go get anymore fish, just to make sure everything is stable.

 

[fishorama]

I'm sorry about your neon. I always try to change water often after a disease or death for a week or 2. You really should have actual numbers for your tank parameters, not just "fine". Any ammonia or nitrite is unhealthy, nitrAte should be under 20ppm.

I usually wait 4+ weeks after a death to add new fish. Keep a close eye on your survivors & good luck.

 

[Tifftastic]

Some fish aren't social, even if they are of a social species. There is a lot of individual difference in behaviour, which is being intensely studied every day in my field. It can be due to differences in metabolic rate, brain anatomy, epigenetic reasons, gut bacteria and a suite of others mechanisms. Infection can be one of those reasons, but it may not be related. However, it is good to pay close attention to changes in behaviour as they can indicate that something may be wrong.

As far as adding other fish. I agree with fishorama, lots of water changes. Get a test kit and don't add more fish for about a month without seeing any signs in the others. That could have been an isolated case, or it could be a bacterial infection or internal parasite and the symptoms haven't shown up in the other fish yet. The symptoms you described can be due to either of those, so it is best to give it some time to tell.

 

[MrDibbs]

I'm sorry about your neon. I always try to change water often after a disease or death for a week or 2. You really should have actual numbers for your tank parameters, not just "fine". Any ammonia or nitrite is unhealthy, nitrAte should be under 20ppm.

I usually wait 4+ weeks after a death to add new fish. Keep a close eye on your survivors & good luck.

Hi, I do I have the actual numbers, and I can verify they are within the desirable ranges. I think my nitrate was just at 20 but then I did a good water change. Nitrite was 0. I will take your advice and keep going with the regular water changes (i'm chaning about 12/13 L per week in my 60L tank that is probably only about 55L with all the substrate and rocks in there). I will also heed your advice and wait about a month before I put any more fish in (these 6 tetras were the first and onlhy ones in the tank).

Lastly, the other 5 are doing absolutely great right now.

 

[MrDibbs]

Some fish aren't social, even if they are of a social species. There is a lot of individual difference in behaviour, which is being intensely studied every day in my field. It can be due to differences in metabolic rate, brain anatomy, epigenetic reasons, gut bacteria and a suite of others mechanisms. Infection can be one of those reasons, but it may not be related. However, it is good to pay close attention to changes in behaviour as they can indicate that something may be wrong.

As far as adding other fish. I agree with fishorama, lots of water changes. Get a test kit and don't add more fish for about a month without seeing any signs in the others. That could have been an isolated case, or it could be a bacterial infection or internal parasite and the symptoms haven't shown up in the other fish yet. The symptoms you described can be due to either of those, so it is best to give it some time to tell.

Hi Tifftastic from my second home of Glesga. How is it back there by the way, I miss it every day!! Thanks for the advice. Are you a professional in this field? I can understand that not every single fish can have identical behavioural patterns, but this particular case was indeed a bit odd. If the neon in question had been eating, either with the other fish, after them, or just picking around later in the day I would have attributed it more to behaviour. However, she was not eating at all for 3 days, combined with the inverted abdomen and crooked spine, something was wrong and my local aquarium shop owner, who I do think he knows he stuff, didn't hesitate to say that there was likely a problem.

The others are doing absolutely great right now. The tank water looks amazing and I ordered the JBL combiset which should arrive pretty soon. I'm doing 12-15L changes in the 55L of water in the 60L tank once a week and can monitor chemical levels in more detail as soon as I get that test kit. BTW, the aquarium shop does free testing and they tested the following: pH, GH, KH, NO2, NO3, Fe, CO2 and conductivity. My new kit will test pH, KH, NO2, NO3, Fe and I can estimate the CO2 with a chart. Is it absolutely essential I test for the other ones my aquarium shop tests for and/or other big tests, like NH3/4?

I'll remember to come back and update you on the progress of the tank over the coming weeks if you are interested in seeing how the situation results.

 

[Tifftastic]

I love it here, I chose to stay for a PhD after a master's. My PhD uses fish to model behaviours. My supervisor studies individual behaviours in fish and how metabolic rate influences them (google search for Shaun S. Killen and you can see a lot of his work if you are interested), another researcher in my department is just starting to look at the effect of gut microbiota in fish behaviours, none of that is published yet though. Its a big field and very interesting.

ombined with the inverted abdomen and crooked spine, something was wrong and my local aquarium shop owner, who I do think he knows he stuff, didn't hesitate to say that there was likely a problem

This sounds a lot like a parasitic infection to me. So, keep an eye on them.

As for tests, I would test for NH3/4, NO2, and NO3. Those are the most important IMO. For certain fish it can sometimes be useful to know conductivity and such, but not usually that necessary.