Large oscar and plec seem to be a bit offish with each other

[ASH74]

Hello, I'm new to this forum and require a bit of advice.
I recently bought a large oscar and a plec. they are currently residing in a 5ft tank and seem reasonably happy with the space they have. However, the oscar seems to be scared of the plec. The oscar is around 9 inches and the plec is not much smaller. They do on occasion have a little coming together, nothing bad, i wanted to know if the plec would harm the oscar. I have a communial tank in the lounge with 4 small plecs and various other fish and they seem fine. any suggestions that i need considering would be a great help.

Thanks

[sprout]

Were the fish housed together beofre you got them? It could be several different problems but with out more details I would be inclined to think its just territory establishment.

Yes a pleco can harm an oscar. Pleco's don't just eat algae, they also require protien. If their specific dietary requirements aren't being met, they will attack their tank mates rather starve. They suck the slime coat off the other fish, and I have heared of them actualy causing wounds.

How big is your tank (gallonage)? Do you test your water? Is the water quality in check?

[ASH74]

The tank is 60 gallons,
The fish were not kept together when i bought them.
The tank is a new set up (2 weeks) and i have tested the water every couple of days, I have
also taken water samples to my aquatics supplier, all results are fine.
I only introduced the fish on Monday afternoon so maybe it is a territory establishing exersize.
It is when the plec swims past the oscar that the oscar seems affraid and occasionally nips the plec's nose.
The plec doesn't seem bothered though.

I will take some pics and send them for you to look at.
I also have no ornaments of plant life in there other than a piece of bog wood, would introducing plants/ ornaments help??

Again thanks forthe reply.

ASH74 (London, England)

[Venom]

Welcome to the forum Ash!

It could be a territory thing. Sadly 60 gallons is only big enough for one of those fish. Especially if the pleco is a common pleco. There just isn't enough room and water to completely sustain those two large bodied fish. Can you post your actually water parameters? Ammonia; Nitrite; and NitrAte; using a liquid test kit? Aquarium suppliers are often unreliable when it comes to testing water unfortunately what they consider acceptable isnt always right. They can often be misleading.

Also how did you cycle your tank? If your tank was uncycled previous to adding the fish your fish may be being exposed to high levels of ammonia and that can be deadly to fish if proper measures aren't taken.

[sprout]

Are we talking imperial gallons or us gallons? The imperial gallon(4.54609 L)) is 20% larger than the United States liquid gallon (3.785411784 L). If its imperial gallons your 60 is basically the equivelant of a 72 (us) gallon tank, wich makes sense since you say its a 5 foot tank. Personally I would prefer a bit more gallonage foe an oscar and a pleco, but with due dilligence on your part it will probably work.

I suspect its just territorial aggression. When you introduce two large fish, they have to establish their respective positions. And their only way of doing so is by scaring the other fish.

With the tank only having been set up a couple of weeks, you should keep a very close eye on your water parameters. Unless you 'instantly' cycled the tank with established media, you ae likely to experience a mini cycle.

[Jon M]

Especially if the pleco is a common pleco.

If it's slightly under 9" I'd definitely speculate a common/sailfin. Even if it's not a common/sailfin and is something like a royal, at right under 9" it's definitely too large for an O/pleco combo in a tank under 100g IMO.

[ASH74]

Thanks for the advice on this.
The tank gallonage is in US gallons, i got the calculations from the internet!
Ive now removed the plec and put him in a 4ft comunial tank until i decide best course of action for him. He seems very happy as this tank is 2ft deep and only has small fish in it:
Tetras
Gourami's
Platties
Mollies
He is a common plec and i measured him when i took him out, he is 9.5 inches.
The Oscar seemed to relax as soon as he was removed,until i tried a large Tin Foil Barb (6 inch) for the night and that went
really bad , Oscar was well pi**ed. I really think this guy is a loner and wants to stay that way,shame as i wanted a mate for him,
(that aint happening).
I must say that the fellow aquarians on this forum are priceless to speak to with thier wealth of knowledge and it is so nice to
know that people are as passionate about fishkeeping as i am. (although this one was a gift for the wife )

Would i stillneed to do weekly water changes as the tank is running on a 15ooLH external filter?

Thanks

I will keep the Oscar on his own and keep you updated on his progress.

Thanks again

[Tom]

Weekly 50% water changes are a basic guideline, the best way of determining how often you should change water and how much to change is by way of testing your own water for nitrates periodically. When nitrates exceed 20 ppm, a 50% water change will reduce them to 10 ppm.
Increasing filtration has absolutely no effect on the nitrates in your tank, nitrates are directly related to how much waste is in the tank, that waste being from leftover uneaten food as well as the waste/ammonia produced by the fish. Increasing filtration, although never a bad idea, will not reduce nitrates. When it comes to nitrates, the filter only serves to provide a place for the nitrifying bacteria to live. That bacteria converts waste/ammonia to nitrates, but doesn't remove them. Although there are products that claim they will reduce nitrates, none I'm aware of actually do. The only practical way to reduce nitrates is by removing them when you do a water change.
I recommend you get an API Master Freshwater test kit.

[sprout]

Since you are in England you may not be able to get an API test kit. But I am sure there is a suitable equivelant available. Look for a test kit that is a liquid reagent type. Not the dip strips, as they are generally considerably less then acurate. I keep a packet of them on hand for quick reference but don't rely on them.

Good move on rehoming the pleco to the other tank. Some oscars 'just don't want company'. Oscars do just fine on their own they do not require company. And at the size of yours you may find it exceptionally difficult to add a 'friend' anyway. Large oscars are very powerfull, and if they don't want something or some one in their territory they will remove it or force it to move on. I wish I could find the before and after pictures of my pinkie. My 15" oscar mistook my pinkie for a snack during a water change one day. good thing she wasn't an aligator or that death roll would have removed my pinkie not just dislocated it........