Switching tank from tank raised the wild caught

[gwand]

I have a 20 gallon long that has only had tank raised fish. I don’t think any of the fish were farm raised, but I can’t be 100% certain. I want to use it to home wild caught dwarf South American cichlids. Given that there are potential immune system differences between tank raised, and wild caught fish, after the tank raised fish are moved should I do a complete water change? Will this lesson the possibility of illness for the new wild caught fish? Alternatively, should I start a new tank from scratch?

 

[Magnum Man]

I would suspect the bulk of issue gunk, is in the substrate, and or the bio film, rather than the actual water

 

[gwand]

I suspect you are right.

 

[GaryE]

I have been able to use tanks back and forth with no disease issues. I do a large water change before - most of the tank. The key thing is not to combine the fish. Sometimes, the farmed fish are carrying things that wipe out the wilds. I haven't yet had it go the other way yet.

I am also getting the impression that after about 6 months, the two groups can coexist. I wonder if our issue is viral.
But nothing bad has happened with recent corys or tetras that were kept apart from wild sourced fish for 6 months and were stable the whole time.

I went close to 20 years with no fish that weren't sustainably wild sourced or home bred. Sine I moved, all local stores carry fish farm fish, and it's been interesting to see. You lose more fish.

 

[gwand]

Glad to hear that. Thanks.

 

[emeraldking]

I'm always fascinated by observing the difference between tank raised and wild caught fish of the same species. It can make a difference in how your perspective on these fish can change.