killer rasbora

phoenix

phoenix

Space Cowboy
Nov 30, 2004
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www.pbase.com
I picked up four H. Rasboras for my 20g planted tank, it already has some snails and two otos in it. Well I came home to find one of my rasboras dead and another one who will only hide under my anubias. I wondered what was going on but now I think I have a pretty good idea. I proceeded to feed them after I had removed the dead one and what I noticed right away was that the largest of the rasboras became very agressive. He zips around the tank like fishy lightning devouring every piece of food he can find, he is now constantly searching the water column for food and trying to eat every little thing that he can see.

Now having a big appetite may not be a crime but it's what I saw next that bothered me. I put my hand next to the glass to encourage the scared little rasbora to leave it's hiding place and go out and eat. As soon as the large one noticed it out in the open it began ramming it at high speed, sort of knocking it over onto its side... the smaller rasbora just took the licking and ran back into hiding. This wasn't a one time incident either, I have now seen this particular rasbora be attacked a handfull of times by the larger one. The third rasbora is also being constantly attacked by the larger one, but not as viciously, and it continues to swim around with the large one despite the attacks.

So now I have one dead rasbora who may have been killed and one very intimidated rasbora who may very well die, not to mention the big bully and his nutty companion. I would like to eventually have 8 in the tank and maybe this would help thin out the agression, but I thought that I had better add them all over the course of 2-3 weeks so my system could get used to the load. My tank is planted well and the plants are growing quite fast, but I don't know if they would be enough to consume the waste of 8 fish who had been added at once... although I could get some bio-spira if an immediate increase in the stock is the only solution....

Here is shot I just took of the tank, I trimmed the ludwigia several inches just a week ago and it has already reached the top of the tank again. (if that helps give you an idea of the growth) The rotala and the bacopa seem to grow equally as fast.
http://www.pbase.com/phoenix_dz/image/38834818

What should I do?
 
add about half of the rest of the planned school now and in a week or so add the rest. if your plants are growing that fast you won't see much of an amonia spike. you will have what is called a 'silent' cycle because of the plants.

the plants love useing amonia because they don't have to deoxidise the nutrient as much and thus it takes less energy to use.

possibly could get away with putting the whole school in and still not have any measureable amonia.
 
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Thank you both for taking the time to reply. Sadly the little picked on rasbora died sometime last night. I will try to drive down to the pet store and pick up 4 more when I get off work today. I hope that 6 will be enough to put this beautiful little bully in his place... and at the same time I'm hoping that it won't be enough to cause any ammonia problems.

Once again I appreciate the replies but I'd like to ask a further question. If this large fish continues to be a serious trouble maker, even in a school as large as 8, what should I do?

p.s. I like your avatar Signus.
 
I had a similar problem w/ a single rosey barb. He got traded in for a distant cousin and everyone was much happier and my life was much easier and I definitely felt less guilty!
 
I would think if your tank is fully cycled it would easily be able to handle the bio load of little rasboras - especially since you have such a nicley planted tank - i would add the rest of the school without any worries personally.
 
Thanks Phoenix. Noticed Jet Black for your avatar as well. :) Awesome choice. Once used it as an icon in AIM. I forget who else has another CB avatar, but that person uses Faye.

If your fish is still a bully after adding the rest of the school trade it in for a smaller one. Maybe the lfs would accept that as fair and equitable. Normally Rasboras don't peck at each other, so this case is pretty interesting.
 
Hey Phoenix, four may not be enough to lessen the bullies aggression. I would opt for six myself. Here is a couple of tricks to try. Rearrange the tank decor before putting the new fish in and then immediately turn off the lights once they are in. In the morning the bully finds himself with a bunch of new tankmates which tends to make them more cautious. This has worked for me a number of times, but you have to rearrange the whole tank not just move a rock from one spot to another.
 
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thanks for the advice all, this is the most annoying little fish i've ever owned. He's a selfish little pig with an emphasis on selfish and an emphasis on pig. It is exciting to watch the vigor with which he eats but it's just out of control.

I crushed up a couple of small flakes this morning during my attempt to feed and he literally ate every single piece. Somehow he manages to dart around and get everything he can see while scaring the other one away from every piece it tries to get. It doesn't stop when he gets full either. He ate so much that he started spitting bits out, and even though he didn't want them, he wouldn't let the other fish get them. He has 'em scared to the point where the other one won't even try to eat. I had to resort to netting the bully and floating him at the other end of the tank, just so the other fish could get something to eat.

I'm going to try and fill out the school to 8 fish tonight. I'm hoping that my plants will be enough to hold off any ammonia problems. I don't want any more to die
 
Phoenix, what ended up solving your problem? My harlequins have suddenly turned aggressive and it seems everyone is chasing and harassing everyone else. One of the males will start it, and then its like everyone starts slamming into every one else. They were just spawning last week. I don't know whats going on. I have a 20 gallon long with 9 (now 8) harlequin rasboras. The two smallest ones are really getting picked on. I just lost one today, and I'm not feeling optimistic about the other.
 
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