Naughty Diamond Tetras

[lillykinloo]

Hi everyone! I apologize in advance that this post is so long. I just wanted to make sure I included all of the details. First, here are some specs about my tank:

37 gallons
pH is 7.2
gH is about 6
farily densely planted with a combination of some real plants (christmas moss, java fern) and some plastic plants with a floating plant as well
open swimming area in the middle
gravel substrate
temp: 78 degrees
1 piece of mopani wood & 1 piece of bogwood
Current Inhabitants: 5 Diamond Tetras (2 females and 3 males, I think) and 3 Pearl Gouramis (1 male and 2 females)

I have 5 Diamond Tetras that seem to be quite aggressive, and I'm not sure what to do about it. They chase each other around constantly (at the moment, one of the female's dorsal fins is practically torn in half lengthwise). Actually, the largest two males chase the other tetras (1 male and 2 females). The diamond tetras were the first fish in the tank, and they've been living in my tank for about 2 months now. As soon as I put them in the tank, they started behaving kind of aggressively. They chased each other around, nipping at one another. I figured they were just establishing a hierarchy, but someone suggested that I remove all of the decorations and rearrange the tank to try to get the largest two males to stop acting territorial. So, I did to no avail. They continued chasing each other.

Since they've been in the tank, they spawned once (this is when the largest male gets most aggressive-he chases a female into the plants and then viciously chases any other tetras that even try to get close to the plants while the female is there). Initially, I didn't know what he was doing. He would chase a female into the plants, and instead of nipping at her (like he does the other tetras), he shakes around really fast in front of her. A few days later, I saw a couple of silver slivers with eyes swimming around, but I'm new to fish keeping, so I really had no idea what to do with them. They're so small, I couldn't net them. I tried catching them with a cup, but I could barely see them. So, I wasn't successful. Yesterday, I rearranged the tank hoping it might help with some of the aggression. Those tetras didn't miss a beat. Today, the largest male is chasing a female into the plants again and doing his shaky-dance. And, the aggression hasn't gotten any better.

About 2 weeks ago, I added 3 Pearl Gouramis. One of the tetras took a nip at the largest Gourami's feeler, but hasn't done it since. They leave the 3 Pearl Gouramis alone (I think because the Gouramis are so much larger). And, the Gouramis seem to hide under the wood in the tank a lot-I'm not sure if this is because they are worried to come out with the tetras or if they are just being shy. So, I was starting to feel hopeful that the Diamond Tetras would be able to live peacefully with others (even if they were mean to each other).

So, last weekend, I bought 3 Cory Cats to add to the tank. The cories were juveniles, so they were not full grown. Unfortunately, the tetras killed a juvenile cory (bit it's little tail off, and it died a day later ). They also chomped part of the tail of another juvenile cory, and I've removed the remaining two cories from the tank.

I ordered 3 Killifish about a month ago to complete my tank community (3 Pearl Gouramis, 3 Striatum Killifish, 5 Diamond Tetras, and 5-6 Cory Cats). The Killifish are so small (about 1 inch long), that I'm afraid to put them in my tank after what happened to the little cories. They came in the mail today, and right now, they're in a pregnant fish holder.

I really would like to be able to have Cories and Killifish in the tank. And, all this fighting is stressing me out (this is why I did not go with a cichlid tank...I enjoy peaceful tanks). I'm constantly going over to the tank to survey the new damage. So, I'm wondering:

1. Should I return the Diamond Tetras to the fish store?
2. Would adding 2-3 more Diamond Tetras help them to act less aggressive?
3. Is there anything I can do to limit the Diamond Tetra's aggressive behavior (besides rearranging the tank; this doesn't seem to be helping unfortunately)

If the answer is to return the Diamond Tetras, are all tetras this aggressive? Would the black neon tetras or any other tetra be a bit more agreeable in my tank (A full grown killi can eat a neon, so neons and cardinals probably won't be an option)?

Thank you for taking time to read my post and for any advice you can offer!

 

[luque]

if i were you i would talk to my lfs and make a deal to buy a few more like you said too opefully lower the agression and if it didn't to be able to return them for maybe another type of tetra or even maybe danios or something up to you. anyway i wish you the best of luck and great choice with the killifish

luke

 

[Majjie]

Hi Lilly,

I haven't kept Diamond Tetras so don't have any direct experience - but they're not generally known to be fin nippers (like Serpae Tetras, for instance) - so maybe getting a few more would help. I'm having trouble with my tiger barbs at the moment - their numbers have dropped to 5 after a few deaths last year and they're now chewing each other's fins. I'm going to bring the numbers back up to 8 because that seems to be the magic number for stopping aggression in very active social fish like these.

As Luke says - it would help if your lfs was understanding and would allow you to take them all back if it doesn't work - otherwise you'll only have a worse problem

You could also try adding more plants. I keep neons, cardinals, glowlights and blue emperors in a very heavily planted tank - tall plants at the back but loads of anubias and the smaller cryptocorynes at the front, to about a third of the tank height (I don't have very high lighting). The peaceful tetras all hang out amongst the leaves (except when they're bickering amongst themselves) whilst the blue emperors speed around the water above the plants (and join in any good fights they come across - but none of this causes any physical damage). This sort of planting might help protect any corys too.

Another thing you could try (if you don't do it already) is feed them a small amount twice a day - instead of a larger amount once a day. I think fish tend to get more aggressive when they're hungry.

If all else fails, though, take them back - or sell/give them to someone with a more suitable tank. I keep mainly danios with my tiger barbs - they can't catch them .

And, finally, no - not all tetras are aggressive. Glowlights and black neons are particularly peaceful. Cardinals are too - and they grow quite a bit bigger than neons (I think people often forget this because the juveniles in the lfs all look the same size)

HTH
Majjie

 

[lillykinloo]

Thanks so much Luke & Majjie! I really appreciate your advice. I'm going to go get 2-3 more Diamond Tetras (I'm going to try to get females, because the two females seem to get picked on the most. Maybe having a few more will help to spread out the aggression from the males so they don't get constantly chased and nipped?). If this doesn't work, I'll see if the lfs will just let me bring all of them back. I wouldn't need my money back. And, I would even be willing to pay for any other fish I selected (like the black neons or cardinals). Maybe they would be ok with this.

Majjie-Thanks for the advice about the planting. I have a very heavily planted tank with an open swimming area in the middle. But, the floor of the tank has two pieces of wood covered in anubias, moss, and java fern. I thought this would be enought to provide the little cories with protection. And, they were fine until the smallest one shot up to the top of the tank for some reason. All five Diamond Tetras went after him. This is when he lost his tail fin. I am going to take your advice about the twice a day smaller feedings. This might help because they do act like they're starving all the time. It's even hard for me to insure that their tankmates are getting enough food, because the tetras are such greedy-guts.

 

[Majjie]

Yeah - it does sound as if you've got plenty of cover - unfortunately corys do that - they like an ocassional gulp of air
Fingers crossed that adding a few more tetras does the trick.
Good luck!

 

[NEONCORY]

I'm going to try to get females, because the two females seem to get picked on the most.

Although you mentioned that you have heavily planted tank, I believe you need more shelter for the female Diamond tetras. When the male tetra peck the female, that is usually male try to check the female breeding readyness. They almost always ready to spawn. Like you mentioned they spawn once in your tank and you also saw the frys. The water parameter is fit for their liking, and that would trigger the instinct of procreation more. Anyway, I know most if not all the tetra male show same type of behavior.(chasing, pecking, body slamming and drive the female into the thicket of the plants and they can spawn. The Neon does it, Glowlight does it, Lemon does it and I'm sure many other does too. It just some may more rough than the other. And when the female is not ready to spawn, they usually fend off the male but sometime the constant harassing from the male, the female need some place to escape. So I would suggest you need more hiding place for the female. You may get them some kind of cave, more drift/bog wood, decoration and/or more plants. So the female can get away from the males when they want to. Also more female would mean, less harassment each have to take. It spreads around. And better odd of one or two female actually ready to accept the male more often. Which gives time to rest for the other females. So getting more female should help your situation.
There are 2 other things you could do but you probably don't want to do since you are keeping them in the community tank. But here it is you decide if you want to implement. If you have another tank or divider, it is possible to seperate the sex. Also, you could alter the water parameter so that the water is not ideal for them to spawn therefore less aggression toward the female from the male. This however is tricky since you have to tinker with temperature or ph or hardness. And any of the sudden change of those or the unstability is not good for the fish. Maybe lower the temperature to 75 up the ph to 7.4 and gh to 15~20. Especially the temperature should help in 2 ways. Lower the temperature would slow their metabolism so less often they are hungry(although they are a hungry fish after all they are so active I can't imagine how much enegy they use for swimming all over the place with such a speed) Also hopefully it would be less ideal condition for them to spawn so less frequency for the male to harass females. I also would feed more if I were you. So female can roe up quicker and she would be ready to spawn more often so less harassment from the males.
Feed them more meaty stuff like some kind of worms(bloodworm,grindal,black,white,tubflix just make sure they are clean and disease free if you use the livefood)
Hopefully something will works for you. Since Diamonds are really pretty active Tetras. I have some but I haven't had eggs from them yet. I think I will try your water parameter and set the breeding tank.