Desperately need help regarding unusual silver arowana aggression…

[maxvenomz]

Hi MFK community, I’m new here, hoping to find some help or suggestions about a very peculiar case (or so I believe).

I have a 72” tank, with a 6 month old silver arowana and 2 oscars (one black one white, both a year and half old) in my bedroom.

During the day time (and when the light is on), everything’s absolutely normal. Fishes happy, playing, eating, no aggression whatsoever.

However at night, after I turn off the lights, the arowana would suddenly go bonkers and start harassing the heck out of the white oscar. Just to be clear…
- arowana harass and bully the white oscar
- JUST the white oscar, not the black oscar, like at all.
- White oscar does not fight back but freaks out from the repeated “drive-by” arowana attempting to bite her (obviously can’t fit in his mouth)
- Plenty of space and plants/hiding spots to block line of sight, but the aggression persists.
- Basically every night since I got the tank, approx. 3 weeks.

I tried looking up other people who may have faced something similar but, nothing came up, almost all threads I found it would be the other way around.

What could be happening? Any ideas? Why only at night and why only towards this specific oscar? I’m desperate

Max

 

[troublesum]

I had 8 2in red terrors 1 female doubled in size by the time the terrors hit the 5-7in range the female was 8in and same thing every night when the lights went out she would focus on just one by morning that fish would be dead.
I'm not an expert but i would assume when the lights thats when the predatory comes out in them

 

[AR1]

Hi MFK community, I’m new here, hoping to find some help or suggestions about a very peculiar case (or so I believe).

I have a 72” tank, with a 6 month old silver arowana and 2 oscars (one black one white, both a year and half old) in my bedroom.

During the day time (and when the light is on), everything’s absolutely normal. Fishes happy, playing, eating, no aggression whatsoever.

However at night, after I turn off the lights, the arowana would suddenly go bonkers and start harassing the heck out of the white oscar. Just to be clear…
- arowana harass and bully the white oscar
- JUST the white oscar, not the black oscar, like at all.
- White oscar does not fight back but freaks out from the repeated “drive-by” arowana attempting to bite her (obviously can’t fit in his mouth)
- Plenty of space and plants/hiding spots to block line of sight, but the aggression persists.
- Basically every night since I got the tank, approx. 3 weeks.

I tried looking up other people who may have faced something similar but, nothing came up, almost all threads I found it would be the other way around.

What could be happening? Any ideas? Why only at night and why only towards this specific oscar? I’m desperate

Max

That is not a uncommon behaviour since i have also faced it.

My silver aro used to do the same with my marbled walking catfish. I thought the catfish was the culprit, since they are known to get aggressive. However upon closer inspection i found out that it was the aro who always started the fight.

This usually happened when the aro was hungry, so are you feeding your aro enough?

Make sure the aro is getting enough food. You can tell that the aro is full once its stomach bulges a BIT.

EDIT: make sure you DO NOT OVERFEED .

 

[yellowfinfmb]

how big is your tank I know 72" but how wide and deep is it because if it not 240 gallons not big enough and that is small tank I have a 670 gallon tank which is 10' x 4' x 30 inches

 

[fishdance]

Just run a moonlight light during the night time.

I use a clip on 10 watt LED that never gets turned off - 24/7 as that's more reliable than a timer on all my aro tanks. Electrical consumption is insignificant. Actually I run 2 of them per tank in case one fails.

 

[Trouser Cough]

Are you sure you're not mischaracterizing what you're seeing? I'm not suggesting that Arowana aren't cranky every once in a while but they do have teeth that point inward, a huge drawbridge mouth, and one w/ a weak hinge at the bottom as well. When they bite something it normally has to go all the way in or physically be coughed back out as the teeth aren't good at releasing anything.

Or maybe I'm misunderstanding. What do you mean by harass, bully and bonkers?

They really only have one tool and it's their mouth. Anything in the tank that comes to know those teeth will usually be killed and eaten as Arowana are not good at bite and release behavior.