Sudden aggressiveness

[markwill]

I established my discus tank (72 gallons) a month or so back with four smallish discus, ranging from 2 1/2 to 3 inches. They settled in nicely with just a hint of a pecking order. This struck me as good news because I had been told that the pecking order was more evident with smaller number of fish, namely things "smooth out" with a larger number.

So, I purchased another three more discus on Tuesday. This time I had two larger ones (perhaps 5 inches or so) and another of about 3 inches. What has surprised me is that a couple from the first batch have suddenly become more aggressive amongst themselves (none of them go after the two larger fish I just bought, although they do go after the 3 inch one now and again). But, amongst themselves, one in particular is very aggressive (he just plain hunts around the tank looking for little ones to chase) and one of the other ones is also more aggressive than before.

Is this to be expected? I was led to believe that any aggressiveness would diminish, not increase. Is there anything I can/should do so stop this?

Thanks.

Mark

[Cosmo]

Mark,

First of all, hopefully you quarantined the new arrivals before adding them into your tank ? If not, keep a very close eye on all of them and make sure the water quality stays up.. your bio filter has to grow some to accommodate the waste of the two new larger fish.

As to the aggressiveness, what you've done is disrupted the established pecking order and started another round of who's on top. The smaller ones are now vying for who's next in line after the big guys. Sometimes, the smaller established fish will go after the new guys even if their larger simply because... well, they're established :)

Hopefully, they'll calm down soon but if the overly aggressive one bullies the little guy too much he may have to be removed for a short period of time to another tank and re-introduced. You don't want the little guy developing stress illness's and becoming runted.

This is one of the reasons it's often said to buy six or more at the same time from a reliable source... that way they all acclimate at the same time and settle in quicker.

hth

Jim

[markwill]

Thank you Cosmo. First, I'll admit that my new additions were not quarantined (I hope members of the forum will still communicate with me :-)). I would certainly not defend this as a good idea - it's a decision based on the fact that I just spent a good deal of money on my overall setup (probably around $1,000, which is quite a lot for a not-quite-yet-fully-wife-supported hobby!!!) and don't have an additional tank and equipment. Not sure if it lowers the risk at all but all seven of my fish have been purchased from the same dealer - a local discus-only dealer who has been selling discus for over 25 years. Of course, that doesn't mean my new additions won't have problems. I'd position this as a "measured risk" on my part - let the flaming begin :-)

In terms of the aggressiveness, the slightly surprising aspect of this is that this is taken place amongst the first batch of fish (4), which were relatively peaceful before the new batch (3) arrived. In relative terms, the new fish have pretty much been left alone.

Yes, your advice about buying 6 or more at once is understood. This was an issue of cost - the two batches have cost me $160 each and I just want to spread the cost a little, especially after that first month with buying the tank and equipment.

Thanks again.

Mark

[Cosmo]

Hey Mark,

I can certainly understand the expense aspect, especially if your wife isn't "yet" fully onboard with your addiction :p Used to do it the same way for much the same reasons :) Problem is, seemed like I'd always lose a fish or two now and then, so if you add up the cost of the fish a quarantine tank may not be as expensive as it first appears.

Here's a little trick that might help ...
Have your wife pick out names for all your fish, this will establish a psychological bond and if any of them don't make it, you just say "you know honey, if only we had a quarantine tank setup before we added (insert new fishes name here), poor little (name of fish just lost) would probably still be swimming around happy like he used to be... (you might embelish here to increase the impact) :D You'll have support for that quarantine tank in no time.. LOL At least it worked for me :p

Not too surprising that it's the four you already had that are up in arms while the new comers aren't. The four established fish are the ones at risk of losing pecking order rights. The new fish know they're not in they're "school" so they take time to get acclimated.. don't be too surprised if they change behavior somewhat in the near future.

Good luck :)

Jim

[markwill]

Hey Mark,

I can certainly understand the expense aspect, especially if your wife isn't "yet" fully onboard with your addiction :p Used to do it the same way for much the same reasons :) Problem is, seemed like I'd always lose a fish or two now and then, so if you add up the cost of the fish a quarantine tank may not be as expensive as it first appears.

Here's a little trick that might help ...
Have your wife pick out names for all your fish, this will establish a psychological bond and if any of them don't make it, you just say "you know honey, if only we had a quarantine tank setup before we added (insert new fishes name here), poor little (name of fish just lost) would probably still be swimming around happy like he used to be... (you might embelish here to increase the impact) :D You'll have support for that quarantine tank in no time.. LOL At least it worked for me :p

Not too surprising that it's the four you already had that are up in arms while the new comers aren't. The four established fish are the ones at risk of losing pecking order rights. The new fish know they're not in they're "school" so they take time to get acclimated.. don't be too surprised if they change behavior somewhat in the near future.

Good luck :)

Jim
Thanks again, Jim. What I have going my advantage is that my kids have already named each of the discus so, although indirect, my wife has started to get a little attached :-) All good!!!

Wha exactly does the quarentine tank require? What's the minimum realistic tank I could get by one (on the assumpption that I might buy, say, 4 discus at a time from 2" at the smallest to 5" at the largest)? Do I just need a heater and filter (sponges alone?). Do discus move from a completely bare tank to one with some features (gravel, artificial plants, etc) without problems?

Thanks.

Mark

[Howie_W]

Wha exactly does the quarentine tank require? What's the minimum realistic tank I could get by one (on the assumpption that I might buy, say, 4 discus at a time from 2" at the smallest to 5" at the largest)? Do I just need a heater and filter (sponges alone?). Do discus move from a completely bare tank to one with some features (gravel, artificial plants, etc) without problems?

Thanks.

Mark

Hi Mark,

Basic quarantine tank requires a heater and a healthy sponge filter. When I start out with a new group of fish I like to go with no less than 6, but usually more, and the larger the tank the better. Average quarantine time is aprox. 6 weeks. Quarantine time can be more or less, depending upon how familiar you are with the breeder/supplier and any information the breeder can supply.

Discus can easily adapt from one set-up to the next; I like to grow out juveniles for a full year or more, and then transfer to a fully planted tank. Some fish will show little reaction, while others take longer to adjust. In general, healthy fish with good appetites will adjust with no problems.


Howie