Introducing new fish into established tanks

Loco Lucas

Exodon
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MFK Member
Apr 25, 2018
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Belgrade Montana
This is something we have had issues with, mainly with our larger catfish.
Yestersay, I tried to place an 8 inch female Oscar into our 210 gallon that is home to our RTC that is pushing 19 inches.
It turned out poorly for the oscar...
We have tried holding the new fish into the sump tank getting all the fish used to the new smell, doing a water change before hand, feeding before hand... adding mutable fish at the same time.
Once our RTC gets it in his head that the new guy is new... he will kill and eat them. Same with our tiger shovel nose cats and our peacock bass.
This becomes an issue... We have to be able to move fish around due to sizing and temprament. Our RTC lives with 6 other fish and they are not even really a snack if you sized them up. But, because they are long time tank mates, zero issues. Our black shark will swim with in 2 inches of our red tail's mouth while the red rail is hunting! Zero issues.
New fish?
If it takes a week, our RTC will eventually hunt them down and eat them.
Thoughts on introducing fish into large predator tanks? IMG_20180428_121840_920.jpg 20180428_122544.jpg 20180428_122544.jpg IMG_20180428_121840_920.jpg
 
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Loco Lucas

Exodon
Original poster
MFK Member
Apr 25, 2018
61
82
26
48
Belgrade Montana
This is something we have had issues with, mainly with our larger catfish.
Yestersay, I tried to place an 8 inch female Oscar into our 210 gallon that is home to our RTC that is pushing 19 inches.
It turned out poorly for the oscar...
We have tried holding the new fish into the sump tank getting all the fish used to the new smell, doing a water change before hand, feeding before hand... adding mutable fish at the same time.
Once our RTC gets it in his head that the new guy is new... he will kill and eat them. Same with our tiger shovel nose cats and our peacock bass.
This becomes an issue... We have to be able to move fish around due to sizing and temprament. Our RTC lives with 6 other fish and they are not even really a snack if you sized them up. But, because they are long time tank mates, zero issues. Our black shark will swim with in 2 inches of our red tail's mouth while the red rail is hunting! Zero issues.
New fish?
If it takes a week, our RTC will eventually hunt them down and eat them.
Thoughts on introducing fish into large predator tanks? View attachment 1312604 View attachment 1312603 View attachment 1312603 View attachment 1312604
And sorry about the multiple photos... getting used to uploading here.
 

Backfromthedead

Redtail Catfish
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Jul 12, 2017
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well your rtc is gonna try to eat anything shy of its own size. I'd wager if you starved him a little while he would take out all of the smaller tankmates as well.

moreover, theres no room for anything to escape in that tank. if you want tankmates you will need a much larger tank or more likely a pond as the rtc will displace half the volume of that tank as an adult...
 

cichla & saratogas

Exodon
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Apr 26, 2018
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When adding to Big predator tank keep the lights off , make sure everyone has ate good for the day , most importantly make sure there they are at least in the same size range , even then prepare for some fins torn and missing scales.
 

Loco Lucas

Exodon
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Apr 25, 2018
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Belgrade Montana
We do not place anything into the tank we are willing to loose... but at some point when the RTC is moved into a larger tank, he will be with other fish. Cats and other large fish. Want to keep him used to being with others. Yes, I understand that it's in their nature to eat what ever fits. I have done this long enough to know that. But when we move into an extremely large tank, we want the tank to have something other than the cat fish. Thus, keeping them with others.
 

Loco Lucas

Exodon
Original poster
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Apr 25, 2018
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Belgrade Montana
We would like to have a 2500 gallon tank with pacu and large cichlids. Throw in mini fish that are expendable and mean enough to survive. We have a 2 inch African cichlid that has been with our RTC for a long time and others. It's as if he could careless aboyt little ones, he wants big ones. We will try the night time thing. That is very easy to do.
 
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Coryloach

Redtail Catfish
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Apr 22, 2015
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It's as if he could careless aboyt little ones, he wants big ones.
Don't we all :)

We do not place anything into the tank we are willing to loose...
The issue I see here is that there is little concern for the fish and more for what one wants. Unfortunately the two are often incompatible, especially when the wants exceed the realms of common sense...

But when we move into an extremely large tank, we want the tank to have something other than the cat fish.
I am not trying to get at you personally but I can't resist throwing a joke...I think your fish maybe more capable of controlling its water quality than its owner can:)
Joke aside, a larger tank and new territories may make things more manageable...Until then....
 

Deadliestviper7

The Necromancer
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Aug 6, 2016
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The more space and hiding places you have, the easier it will be for fish to avoid being eaten,so once you put him in the bigger pond he'll have a much harder time killing other fish.
 
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