Strange Behaviour!?

[beff]

Hey guys,

Joined this as today I went to my local aquarium. I saw a range of Siamese Fighters that looked amazing. I asked the assistants if they would get on with my Red Fin shark (the only non-communal fish in my tank, I also do not have guppies which I know fighters dislike). He said they in fact had a fighter in with four young red fins, so that was the green light.

Whenever I add something to the tank my shark usually shows off his dominance, and makes it clear that the tree ornament is HIS place. Bear this in mind.

I added in the fighter, who at first kept to himself, and got on with all the other fish fine. The shark didnt even realise he was there. However when they did meet it was strange. My shark did not chase him like other fish, and they just keep following each other around slowly, very strange and kind of cute as my shark is pretty grumpy!

Anyway, Im a bit alarmed atm, because just now they were swimming slowly round the tree, and the fighter was flaring his gills. I know this means either courtship or aggressive behaviour. They are swimming around the tree.

Given the peaceful behaviour previous, is this just a dispute over who chills where that will be solved, is it some weird little love thing, or did the aquarium assistant lie to me and I should take the fighter out and return it before someone kills someone?

Please help!

 

[beff]

Been looking online and seeing nothing about these two not getting on? Dont a few compatibility tables and nothing reallh indicates its a bad choice.

 

[Jonty]

How big is your tank? If the fish you're talking about is a Red-tailed shark, it reaches 8 inches in length, needs a 55 gallon tank and usually gets very aggressive. They may get along ok while the shark is small and they keep out of each other's way, but I'd wager the shark will attack the betta.

What else is in the tank?

 

[beff]

We have had the shark a year and he's barely grown since I got him... hes about 3/4 inches. AKA Rainbow shark right?

Just had a look again, the shark is hiding from the fighter?

Other than the shark, we have 2 bloodfins, 3 rummy nosed tetras, 2 neon tetras (VERY old hence why they are no longer in a school), 3 plecos, 2 rainbow neons. Im rebuilding my tank slowly after I bought some diseased fish (from a known national chain) and left me with only the shark and 2 neons. I need to measure the tank as I cant remember how big my bf said it was, but its twice the size of the ones at the local aquariums (not a great judgement I know!). About 100L. Plenty of hiding places too, wont be adding any more fish really.

I have read that its down to the individual personality of the betta, and he WAS in with a few of these sharks anyway (though they were a bit smaller than mine admittedly)

 

[Jenste]

the reason he was probably getting on with the other sharks, is they are all very young and territorial instincts kick in around maturity.

also...you need to do research before getting fish....
your 100liter is too small for the shark! you need to re home him - - plenty of hiding places sounds all well and dandy - but remember that every ornament you add takes AWAY from the swimming room.

your best bet would be to get rid of the shark, and set up a small heated/filtered tank for the betta. then build the 100 liter up as a community.

the betta is not compatible in your current tank because of the shark, and your tetras - - tetras are known fin nippers and will end up destroying your bettas fins! (very painful to the betta!)

 

[beff]

Ok, thanks for your help! I considering another tank anyway, for other fish that cant be kept with what I have in the 100L. I also know to be more cautious with advice, as I listed what i had in the tank and our tank size before buying. I should know the tetras were fin nippers anyway! DUH.

Watched the tank for a long time this morning, very tranquil, no problems with the shark or betta,

This will sound stupid, but another general question: how long do the sharks take to grow to their full size? I dont believe that "they only grow to their tank size", but hes only grown a small amount since we got him... we got him as an adult anyway. He is not quite 3 inches, the same size as what we got him a year ago. They live a good few years so is it a slower process than smaller breeds?

I figure I should wisen up and ask all the questions Ive never had anyone to ask!

 

[Jonty]

They grow to 6-8 inches I think. Are your Plecs common plecs? If so, they grow to over a foot in lengh, produce a lot of waste and you need at least 200l for one.

 

[Jenste]

he might still be small because your tank does not offer him the room he needs - - in other words, you are stunting him.

need to rehome or upgrade asap