# Aggressive Fish Problem



## Tiibiigiibii (Jun 9, 2015)

I'm relatively new to having an aquarium. I've had a 10 gallon aquarium for about a month and a half. Up until about 5 days ago, I had 2 glo fish tetras, a neon tetra, and a pleco. Last Friday, we added 2 more neon tetras, 2 more glo fish tetras, 2 black neon tetras, and 2 glo fish danios. Sunday, we noticed that one of the new neon tetras was just gone. No sign of him at all. The water levels were normal. We assumed that since he was so little he just died. Last night, we noticed that the other neon tetra had been attacked and was missing a fin. This morning, he was dead as well. I didn't think that we had a compatibility issue since they're all non-aggressive fish. I've heard that sometimes neon tetras can get territorial, and the one that we've had the longest was double the size of the other two. Is it possible that he's the culprit? I just need to know which fish might be the cause of this to insure that it doesn't happen to anymore of the fish. Thanks.


----------



## MustangTess (Jun 9, 2015)

my first suggestio is to watch your tank it will become obvious which fish(es) are being agressive. Fish are like people just because a species is rated as docile dosent mean thay all are. We have eons but we have many of them in a school. not sure of the behavior with just a couple of them. most fish I buy in threes of not more which helps prevent too much territory fights, however a fish that has established a territory will always defend it unless you move it to a new tank for awhile and introduce it back several weeks later with the new fish. I have bettas and have simular issues in my sorrority tank at times, and also with any breeding or older cichlids.

Fish that are introduced really need hiding places and should be of simular size when possible. Note any fish bought in a pet store can be sick even if it isnt showing signs. I would suggest getting a 5g hospital/ quarentine tank and placing all new fish in it before placing in your 10g to prevent diseased, sick or parasitic fish taking out your whole tank.

I usually quarantine for atleast a week and in some cases 2weeks just depends on where i rcvd the fish from.


----------



## henningc (Apr 17, 2013)

I'd say the Black Neons are the issue. All of the fish in your tank need to be kept in groups of 5-8 to be comfortable. The Black Neons are bigger, faster and tend to be aggressive when insecure. 

The biggest issue you will have is tank size and a 10gal is just limited. Unfortunately, you passed the limit. I don't know much about what you call a Glo Tetra, but if they are small and none-aggressive 5 of them and 5 Neons is more than enough for your 10gal. Don't know what type of pleco you have, but unless it is a dwarf species it will out grow the tank. Common plecos can grow to 6"-8".

Sorry to bring the bad news. You may wish to look on Craig's List and pick up a 20 high or 30gal to house the group once filled out. Please don't hesitate to ask before you buy.


----------



## kalyke (Nov 19, 2014)

Fish tend to eat the cadavers of dead fish, even their buddies, so I would not be sure the fins were eaten before or after death. They will also harass a dying fish. Neon tetras are legendarily weak fish and bad shippers. Anything could have killed them. I like the way they look but would never buy them. Small fish like endlers are more hardy. Okay, anyway. Yeah, in a 10 gallon, you are quite over stocked. Please consider a larger tank!


----------



## Tiibiigiibii (Jun 9, 2015)

Since I first posted this message, the problem has gotten worse. A couple of fish in the tank came down with ich. Since the fish were under warranty, we took the one that died along with a water sample back to the pet store. The people there blamed our problems on our pH and nitrate being high in our tank. We corrected the issue and began treating the ich. However, we lost another fish shortly after that. I'm starting to think it's a parasite because last night my husband noticed that two more fish were dead with their fins eaten off too. The weird part was that when he went to get the second one out, there was a small bug eating its body. Today, I discovered another dead fish with the same markings. Also, the glo tetra (which is basically a skirt tetra that has been genetically modified to glow under blue/black led lights) that is the biggest in the tank and has been in there the longest is showing signs of something attacking it too. We're now down to 2 glo tetras, 2 danios, and 1 pleco. The black tetras and the neon tetras were killed by whatever this is, so I know that it's not them. The well glo tetra stays to himself and doesn't bother any other fish. The danios do tend to chase each other, but I've never seen them mess with any other fish. Overstocking is no longer an issue, and there's plenty of room for the fish to hide and be by themselves. I don't know what it could be.


----------



## MustangTess (Jun 9, 2015)

treat the tank be sure that you fish are healthy. tetras can be nippy but sounds like you might have a parasite or bacterial infection in your tank. so you quarateen your fish before putting them in your tank? any one of the fish you bought could have brought something into you lil family of fish.


----------



## brads (Mar 23, 2013)

MustangTess said:


> treat the tank be sure that you fish are healthy. tetras can be nippy but sounds like you might have a parasite or bacterial infection in your tank. so you quarantine your fish before putting them in your tank? any one of the fish you bought could have brought something into you lil family of fish.


First , I'm sorry this is happening to you and your fish. Totally agree with MustangTess. Impossible to pin the blame on any one thing but at this point I'd treat for everything. Parasites, bacteria, the works. Since everything was Ok before you put the new fish in I'm gonna guess they brought it with them from your LFS. All too common unfortunately. They should quarantine their fish before selling to be safe so... Also a good idea for you to have one too. Just saying.  Good luck


----------



## Tiibiigiibii (Jun 9, 2015)

Thanks for all of the advice. The remaining fish are alive and well now. I have decided to avoid buying fish from that pet store. The first time that I tried buying fish from them, all of the fish had ich, and they weren't selling any fish. Then this happened when I actually bought fish from there. The store is part of a small chain. My friend has had issues with sick fish from another one of their stores as well. It must be an issue stemming from their distributor or something. I never would have thought that Walmart would sell healthier fish than a local chain. Go figure.


----------

