Advice

[Big B]

Are there any types of fish that are listed as community fish at the lfs but can be aggresive when put with certain types of community fish?

The reason I ask is that I have a few fish that I have noticed "chunks" out of their fins. The fish with the damaged fins are (4) Red-eyed tetras, (1) Glow-light tetra, and (1) Irredescent shark.

I have an older style 55 gallon tank that has been up and running for about 2 months. I had a problem with Ick about 2 weeks after setting up the tank but I haven't had any problems till now. The only fish added in the past (2) weeks were the balloon mollies and I bought the scissortails this past saturday.

Inventory;

(3) Red-tailed Sharks
(2) Irredescent Sharks
(1) Pleco Cat
(5) Glow-light Tetras
(4) Red-eyed Tetras
(4) Albino Black Tetras (Die Injected)
(2) Blue Guoramis
(2) Opaline Guoramis
(1) Black Neon
(2) Giant Daino
(3) Balloon Mollies (1 male/2 females)
(3) Scissortail Rasbora

Any help or advice would be greatly appreciated.

[Faramir]

Blue gouramis and RTBS can be aggressive. Three of the latter in a 55 is likely to end up messy, unless you have a lot of furniture dividing the tank up.

You know that iridescent sharks can get a yard long?

[Big B]

I have noticed the red-tailed sharks appear to be aggresive but only towords each other. I haven't noticed the blue guoramis bothering anybody though. I found out about the size of the irredescent sharks after I bought them. Beginner mistake I guess. If I had to do it again I would have researched a little better. I bought (3) red-tailed sharks originally and now (1) of them is twice the size of the other (2). Could this possibly be the culprit?

[ChilDawg]

I wouldn't bet against it. RTBS's are not happy with any other bottom dwellers, and you apparently have a dominant one in the making (especially since he is twice the size of the other two!!!)

You have too many gouramies, though...two to a tank is the maximum recommendation for any tank. While I may venture to guess that the shark messed with the tetras, the gouramies are also likely culprits.

You are also short of schools with the tetras, and you may have a problem in that there are too few and aggression amongst them cannot be spread evenly.

Here is what I see necessary to your future success with the tank. Keep in mind that I am not talking about safe stocking levels!

Return at least two of the RTBS.
Either get a school of black neons or return the one which you have.
Make sure that you have at least 6 of the tetras/rasboras/giant danios or return the rest of them.
Return the Irridescent Sharks.
I need to know a little more about the Pleco--species and final size will aid me in determining if the Pleco is compatible with the remaining RTBS.
Return a pair of Gouramies.

I hope that this helps. Keep in mind that these are only suggestions, and that you may want other opinions on the matter!

[pinballqueen]

I agree that the culprit is probably the RTBS. They don't like much of anything, to be honest.

You might also want to watch your pleco, if it is a "common" pleco and anything over 3 or 4 inches, because they sometimes will "hitch rides" on the backs of slower-moving species to eat the slime coat that covers the fish. Mine used to attack my gouramis all the time.

That iridescent is going to go nuts in that tank before long. I had made the same error you did in buying one, and it would pound the glass ceaselessly and panic, finally playing dead, upending in a corner. It scared me to death when it did this, and it was miserable, so I took it back. (I, too had a 55 gal.)

To give your tank a safe stock level AND eliminate a lot of the aggression, here's my suggestion. Pick which tetra or danio breed you like the best. Trade the rest in, and form a school of the one you like. You might get by with two species, if they are smaller schools, only 6 or 7 specimens each, but one big school of 15-20 individuals will be a lot happier. I would only have one or two gouramis, as was already suggested. Keep in mind that blue gouramis can get to be pretty big. I'm not sure about the other species you have.

A single RTBS, and a pleco, either a small breed like a bristlenose or a common that you would be willing to trade in every few months due to size would round out the group, and everyone will be a lot happier.

[Big B]

Is (2) guoramis applicable to any size tank?

I have noticed that the lfs always has a number of them in each tank and other species mixed in as well.

Is the size differential between the tetras and guoramis an issue as well?

It is just a common pleco that I have.

Now I am faced with a dilema. Of all the fish we have, our favorites of the bunch are the guoramis. I am seriously considering a second tank.

Thanks for the help.

[ChilDawg]

From what I have been told, yes, two (aggressive) gouramies to any size tank. My guess is that, since, gouramies are such hot sellers, your LFS can get away with overcrowding. Your blue gouramies should go to another tank, since they will kill about anything else that you have.

The common pleco is a little too big for the tank, but will hold up well against any of the RTBS's. I don't think that he will cause any problems with them in a larger tank, but, vigilance is the answer, my friend.

I agree with PBQ on reducing the tetras/rasboras/danios to a school or two, but the size differential, as you said, might make them a big-time target for aggression. Optimally, you may want to have three or four tanks if you intend on keeping the whole bunch which you have (and making them happy with stocking levels for "conspecifics").