Tropical Fish Keeping banner

Neon Tetras are killing each other!

29K views 34 replies 5 participants last post by  Byron 
#1 ·
I had 3 small clown loaches in my 29 gallon tank. I added 11 Neon Tetras and the Loaches killed 3 in 24 hours. I returned the Loaches and got 2 new Neons for a total of 10. The 10 Neons are now fighting with each other and 5 have been killed. There are at least 2 really aggressive ones. One is really fat and bigger than the rest. Any ideas why this is happening? I keep reading i need to add more but I had 10. That should've been plenty right? My tank is cycling, but i doubt this has anything to do with it.
 
#2 ·
Cycling does indeed have to do with it, as I'll explain.

Shoaling fish like all tetra need to be in a group, as you clearly know. Part of the reason for this is the hierarchy the fish will establish within the group. This manifests itself differently depending upon the species, but it is an inherent need of the species. When the fish are settled, and free of stress, there will usually be no significant physical damage with most species [some are different, like Serpae Tetra who will fin nip regardless]. But when the fish is under stress, this changes, and usually for the worst.

Ammonia or nitrite above zero is very stressful. The higher either level is, the more stress. There is also internal damage being done, and this adds more stress. Keeping the fish in too small a group can cause this too, as can too small a tank space, just so you know and to complete the picture.

Fish have few ways of dealing with stress. Sometimes they become weak and waste away, refusing to eat. But more often they take the opposite approach, and increase aggression. It is their only way of fighting back their frustration.

I certainly wouldn't add more fish until this settles down. Meanwhile, make sure ammonia and nitrite are at zero by doing daily water changes using a conditioner that detoxifies both, such as Prime or Ultimate. Are there live plants? Not only do neons and most tetra need the shelter of plants, and floating plants especially; these also help with the cycling.

Byron.
 
  • Like
Reactions: BarbH and ZivaD
#3 ·
Thanks Byron. I have been doing about 20% water changes every day and my ammonia is at 0.25 ppm. Nitrite is 0. I do have live plants. About 12 of them. Only one floater, a water sprite. I have a couple hornwart which supply plenty of hiding also, plus I have a few decorations perfect for hiding. I will just keep the fish i have in there until it is finished cycling i guess. My worry is they will kill each other and then i will not have any fish to continue cycling.
 
#4 ·
FWIW - the clown loaches likely did not killing your neons - they are more likely to be consuming the neons after they have succumbed (to the toxic water conditions).
Neons are not hardy fish, so adding them while cycling the tank is really just flushing your $$$ down the toilet. If possible, I would suggest returning all the fish and proceeding with a fishless cycle - then stocking your tank.
 
#7 ·
No, please stop here. You do not want to change horses in midstream.:shock:

While it is true about the cycling, it is occurring or the fish would all be dead not from aggression but sheer poisoning by ammonia and nitrite. Let's continue with what is started, and build on that when it is settled.

Aside from this, with live plants...and the floating you mentioned are ideal for this...it is possible to "cycle" without affecting the first fish. I've set up dozens of tanks from scratch with fish in them on day one and never had "cycling" issues just by using live plants.

We'll have to go into more detail on what you actually did from day 1 to see where things went wrong. I assume the clown loaches are gone now?

Byron.
 
  • Like
Reactions: earthgirl
#9 ·
Daily partial water changes of half the tank. Use a good conditioner, in this situation one that detoxifies ammonia and nitrite is wise. Prime does this, as does Ultimate. Do some vacuuming of the substrate in open areas when you water change.

This should get things stabilized with the plants. What to do with the mean fish I'm not sure. I suppose let nature take its course.:|

Byron.
 
#10 ·
I will get some Prime. Do I add it in with the water in the bucket before i put it into the tank or do I just change 15 gallons and then put enough Prime for 29 gallons? After the first use, I would assume in the bucket (new water) only. Is this correct? Also, after "nature takes its course", what do I do to keep the ammonia up to complete the cycle?( I want glass catfish, cherry barbs and Neon Tetras by the way). Stock new fish?
 
#13 ·
Boredomb has answered some of this, and I concur. As you are using buckets for the water change (as opposed to a Python connected to the tap to refill) I would add the Prime to the bucket of water.

The plants handle ammonia (and there is no nitrite) as B said.

Wait until everything is settled before acquiring any new fish. Once the tank water is settled, it may be necessary to do something about the neons. One thing you do not want is a nasty aggressive couple of fish when adding something as sensitive as Glass Catfish, they will be shredded.

Byron.
 
#11 ·
You don't want the Ammonia above 0 in a tank with fish in all honesty.
That's why others have suggested the daily water changes and adding a conditioner that detoxifies it. I would stick to that but would also suggest adding more plants. They do amazing job of filting out the ammonia as its a food source. Floating plants such as your water sprite and fast growing plants are what will do best here. Through really more plants in general. Your tank will still cycle but just in the background undetected by test and harmless to fish.

As for the amount of Prime to use I wouldn't use more then the volume of the tank at first until the ammonia is gone then back down to just the volume of water add back to the tank during the water change. You can just add it to the tank then add the new water.
 
#15 ·
OK. I will do 50% water changes nightly (using Prime) and monitor the Neons and do this until I get a 0 reading of Ammonia. I will remove any Neons that are injured and most likely start with a fresh batch when the tank is settled. Thanks for the advice. I will update this thread if I need more advice.
 
#17 ·
So I may have discovered the problem. I tested my tap water and the ammonia was 0.50 ppm. Basically my tap has ammonia. I was using water conditioner but I bought prime last night. There are 2 survivors and they are getting along fine now. Every ammonia test I've done for the last 2 weeks has been 0.50 ppm. Do I need to buy bottled water for water changes?? The last 2 days I am seeing nitrate. I haven't measured any nitrite since I started the cycle 2 weeks ago. Any thoughts??
 
#21 ·
I haven't measured any nitrite since I started the cycle 2 weeks ago. Any thoughts??
Ohhhh... I thought you hadn't measured for it... not that it measured zero. Sorry.

Jeff.
 
#18 ·
Test for nitrites, just so you know, it only takes a moment.

In order to see what is happening with the ammonia, test the tank at different times after your water change. immediately after if you read 0.5ppm that is expected, the Prime will have this detoxified so it is harmless but still shows on the test. Test again a few hours later and again later or right before your next change if you are still doing them daily. You should see the ammonia drop fairly soon after adding the new water as the plants and/or biologicals soak it up. This just lets you know what is going on and you don't need to keep doing.

If you haven't checked for nitrites in two weeks and your ammonia levels have always been 0.5 and you are seeing nitrates now I think that perhaps the issue may also have been a nitrite spike, albeit small, everything adds up.

Jeff.
 
#19 ·
I agree. And Trav, what is the pH of your tank water and tap water? IThis too has a bearing on ammonia/ammonium. Remember to shake tap water vigorously for a few minutes before testing.

Just so you see the light at the end, the .5 ammonia in the tap is unfortunately but not trouble if it is handled correctly. A conditioner that detoxifies ammonia at the weekly [when things are normal with weekly water changes] water change will deal with the initial influx of ammonia, and by the time it becomes ineffective in a day or two the plants and bacteria will have deal with it.

Byron.
 
#23 ·
So when can/should I add more fish? I only have 2 neons in there right now. I know I need to continue to get ammonia in the tank to create the bacteria. I just want to make sure I do the right thing.
Posted via Mobile Device
You have live plants, they will deal with ammonia, and you don't need to be adding it in any form, it will occur naturally. For one thing, it is in your tap water.

There may still be some confusion over "cycling" and plants, so let me explain this once more. When you have live plants, especially fast growing such as stem and floating plants, they will take up much of the ammonia produced by a few fish and the breakdown of organics by bacteria in the substrate. The nitrifying bacteria will still appear but they will be minimal because the plants out-compete most of them for the ammonia. Our test kits will not be able to register ammonia or nitrite because of the plants.

Now, you are adding ammonia with the source water and this is all at once, which is why you are seeing ammonia on tests. But the Prime changes ammonia to non-toxic ammonium. The plants and bacteria take up the ammonium just as ammonia, so there is no change except the ammonium is not hurting the fish.

As long as the plants are growing, you can add a few fish, slowly. Here we come to the aggressive neons...are the two left the bad guys?
 
#25 ·
Yes they are the two bullies. I am going to replace them and start fresh. I still want neons and glass catfish and cherry barbs. Should I stock a different species first?
Posted via Mobile Device
Fish, like the leopard who doesn't change its spots, won't change behaviours, so I would get rid of the two neons. Will the store take them in exchange? Adding other neons to your existing aquazrium with these two will be risky, as the two are in their space and clearly want to own it. In the store tank, they may be out-competed.

If cherry barbs are you choice, I would add them first, a group of 7 would be nice.

Byron.
 
#27 ·
This is a bit tricky to answer. From the perspective of water chemistry/biology, I would add the Glass Cats last as they are by far the most sensitive. But there is also the issue of the neons and barbs getting settled, and then the "intruders" arrive and could get picked on. But if the plants are good and thick--and before the Glass Cats are added I wold have a thick planting including lots of floating plants like Water Sprite--the GC should be OK.
 
#28 ·
sounds good. I will get some barbs and I will also take a picture of my aquarium and post it for advice on more plants/ placement etc. One problem I have as far as floating plants is water sprite is really hard to find around here. I ordered one plant online and was $23 to get it shipped. Also, they sent a potted one that I had to take the pot and rock wool off of. As far as planted plants go, I like hornwort and have some in my tank. I wouldn't mind getting more if you think that is a good, bushy plant for hiding.
 
#29 ·
Wisteria would be good, if your light is sufficient. Planted in the substrate it forms thick bushes. It can also be floated. Brazilian Pennywort is a nice plant when floated.

If I lived in the USA I would send you some Water Sprite. But I have had bad luck getting plants across the border, US Agriculture do not like live plants coming in for fear of disease and other issues, and the holdup usually kills the plants so I won't try as it is too expensive for me and they don't make it.
 
#31 ·
I have added a picture of my tank to My Aquarium. I do not know how to put a picture in this thread. I believe I need more plants. This picture does not show the Water Sprite. Any help with placement to protect my fish would be great. Any suggestions would be appreciated.
 
#32 ·
That is a nice start. The three plants along the front are Java Fern. These should not be buried in the gravel, the rhizome (the thick "stem/root" from which the true roots and leaves grow) may rot if buried. It is best to attach these to rock or wood. I like to stick the rhizome into a crevice in a piece of wood, or you can use black cotton thread.

Some more wood would be good. I like Malaysian Driftwood, it has others names sometimes, it is very dark brown and heavy so it immediately sinks. Some pieces (all are different, being true wood) have tunnels and crevices which is good for many fish. The long pieces can be stood vertically to resemble tree trunks. Have a look at the photos of my tanks, this wood is in all of them. Petsmart usually carries this wood, and other stores.

And more floating plants, lots of floating plants.:lol:
 
  • Like
Reactions: Tropical Trav
#35 ·
To answer your earlier question which I missed (sorry), how to add photos in posts.

When you type a new post, in the area below the window under the blue bar headed "Additional Options" there is a button "Manage Attachments." Click on that, and a small window will pop-up. Click on "Browse" to find the picture on your computer (it must be a jpg file) and double click that. Then click the "Upload" button in the small window, and it will.:)
 
  • Like
Reactions: Tropical Trav
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top