Upgrading Tank - but what order to do everything?

So I’m planning to move all the occupants of my 125L (30g) tank to a new 350L (90g). The new tank has been set up since before Christmas and I’ve put some mature media from another tank into the filter. There’s currently 5 guppies in there just as temporary residents (they look tiny in there!) Parameters fine (0 amm, 0 nitrites). So I’m ready to start stocking up. But what order should I do it?

The 125L has 2 filters running, and theres
- 1 BN pleco
- 2 female Pearl Gourami
- 5 cardinal tetras

In the new tank, I’m planning on
- 1 BN pleco
- 5 Pearl gourami
- pair of Angels
- 20 cardinals

what’s best to do next? Should I start stocking the new tank first with the extra fish, and then add the guys from the old tank, or transfer from the old tank and then buy the new ones. Transfer all the existing fish at once, or in stages? And can I trust that the seeded filter can keep up with the new additions, or move one of the filters over from the old tank?

thanks for any advice!

 

I would put what you already got in there first. Then would build up the tetras next, then the gouranis, and angel fish last.

 

Thanks! Should I shift all the existing in one go, or do you think it would be better bit by bit?

 

Either or would be fine. Just keep an eye on parameters with the increased bio-load.

 

Will do - no excuse now not to get on with it this weekend now. Thanks!

 

I would put what you already got in there first. Then would build up the tetras next, then the gouranis, and angel fish last.

Agree with this. I'd also let your cardinals grow a bit and then add juvenile angels. This will give you the best odds against the angels eventually snacking on them (though it's still a possibility).

 

I’d move them all at once. Will your old filters fit on the new tank temporarily? You can either move their filter with them or take out the media in the filter and put it in your new filter. Most of your nitrifyers are in your media but they also live in the substrate. Because of that I’d move the fish and media and then wait a week before slowly increasing the stock. After a couple weeks you can slowly remove parts of the old media/filter as the new filter will be more seeded by then.

 

Agree with this. I'd also let your cardinals grow a bit and then add juvenile angels. This will give you the best odds against the angels eventually snacking on them (though it's still a possibility).

I was planning originally to stock mainly with angels - getting 5-6 juveniles. But I had advice that it would end up a war zone when they grew up and I’d end up left with a pair of angels and I could fill in with Pearls. So, I thought that the better option would be to start at the end point and buy an adult pair of angels at the beginning. Does that make sense, or is my original idea of 5-6 angels with my existing 2 pearls worth a try?

I’d move them all at once. Will your old filters fit on the new tank temporarily? You can either move their filter with them or take out the media in the filter and put it in your new filter. Most of your nitrifyers are in your media but they also live in the substrate. Because of that I’d move the fish and media and then wait a week before slowly increasing the stock. After a couple weeks you can slowly remove parts of the old media/filter as the new filter will be more seeded by then.

Yes, one of the two is an external canister so it should be pretty easy just to hook it up as is onto the bigger tank. I think I’ll do that if I’m shifting all the fish over in one go.

 

I was planning originally to stock mainly with angels - getting 5-6 juveniles. But I had advice that it would end up a war zone when they grew up and I’d end up left with a pair of angels and I could fill in with Pearls. So, I thought that the better option would be to start at the end point and buy an adult pair of angels at the beginning. Does that make sense, or is my original idea of 5-6 angels with my existing 2 pearls worth a try?

That's tough. Purely looking at it from the angels perspective, buying an adult pair would prevent some potential issues with ending up with multiple pairs in the future that might cause aggression problems.

But adding an adult pair of angels to a tank of Cardinals could end up bad for the Cardinals. Adult angels are definitely big enough to eat Cardinals, so you are relying on the angels not being interested or not seeing them as food in order to avoid that. In this scenario, that is less likely than if the angels grow up with the Cardinals and the Cardinals are fully grown before the angels get so big.

One option could be to start with 5 or 6 juvenile angels along with your other stocking and keep whichever pair up while rehoming the others. Just depends on if you want to do that. I also think a 90 gallon could probably support more than 1 angel pair given adequate structure/territories, but again it will just depend on the angels personalities.

Adding the 2 adults may work, I don't want to say it definitely wont. . But it may turn out really bad for the Cardinals as well. Angels with smaller thin bodied fish like cardinals is just kind of a crapshoot overall.

 

I'd move all the existing fish to the new tank and use the original tank for quarantining the new fish.

 

That's tough. Purely looking at it from the angels perspective, buying an adult pair would prevent some potential issues with ending up with multiple pairs in the future that might cause aggression problems.

But adding an adult pair of angels to a tank of Cardinals could end up bad for the Cardinals. Adult angels are definitely big enough to eat Cardinals, so you are relying on the angels not being interested or not seeing them as food in order to avoid that. In this scenario, that is less likely than if the angels grow up with the Cardinals and the Cardinals are fully grown before the angels get so big.

One option could be to start with 5 or 6 juvenile angels along with your other stocking and keep whichever pair up while rehoming the others. Just depends on if you want to do that. I also think a 90 gallon could probably support more than 1 angel pair given adequate structure/territories, but again it will just depend on the angels personalities.

Adding the 2 adults may work, I don't want to say it definitely wont. . But it may turn out really bad for the Cardinals as well. Angels with smaller thin bodied fish like cardinals is just kind of a crapshoot overall.

Many thanks for the detailed reply. It looks like the weak spot of my plan then is really the cardinals. I love those guys, but it sounds better for them if I go with that adult angels plan to keep them back in the old tank and instead choose another school of larger bodied eg tetra? for the new one.

or as you say, keep with the cardinals plan and go with juvenile angels but knowing that I might have to part company with some of them down the road, plus the cardinals might still end up as lunch.

any suggestions for smallish (so I can have a large group) but not so vulnerable as the cardinals options? The idea was that the cardinals would add a splash of colour

 

Many thanks for the detailed reply. It looks like the weak spot of my plan then is really the cardinals. I love those guys, but it sounds better for them if I go with that adult angels plan to keep them back in the old tank and instead choose another school of larger bodied eg tetra? for the new one.

or as you say, keep with the cardinals plan and go with juvenile angels but knowing that I might have to part company with some of them down the road, plus the cardinals might still end up as lunch.

any suggestions for smallish (so I can have a large group) but not so vulnerable as the cardinals options? The idea was that the cardinals would add a splash of colour

I think any fish that's "taller" instead of long and short would probably be safer. You just want to avoid them fitting nicely into an open angelfish mouth .

I also don't want to discourage you, as I don't think your original plan is a definite "no". I just wanted to bring up some watchouts/concerns and tips I picked up from my own research.

Full disclosure: I have a 75 gallon with a school of cardinals and 2 angelfish (amongst other fish). The cardinals are nearing full size and I did add the angels as small juveniles. The angels are now pretty large (large enough to fit a cardinal in their mouth if motivated) and so far show no interest at all. But even then I know it's still a possibility so I keep an eye on it and have a backup plan in case the cardinals start disappearing. Worth it to me because I really wanted to try both. But if I didn't want to worry about it at all I would have went with one of the "taller" schooling fish species.

 

I think any fish that's "taller" instead of long and short would probably be safer. You just want to avoid them fitting nicely into an open angelfish mouth .

I also don't want to discourage you, as I don't think your original plan is a definite "no". I just wanted to bring up some watchouts/concerns and tips I picked up from my own research.

Full disclosure: I have a 75 gallon with a school of cardinals and 2 angelfish (amongst other fish). The cardinals are nearing full size and I did add the angels as small juveniles. The angels are now pretty large (large enough to fit a cardinal in their mouth if motivated) and so far show no interest at all. But even then I know it's still a possibility so I keep an eye on it and have a backup plan in case the cardinals start disappearing. Worth it to me because I really wanted to try both. But if I didn't want to worry about it at all I would have went with one of the "taller" schooling fish species.

Thanks - good to know in advance the potential problems. I’ll take a look at some chunkier tetras.