Moving Gsp To Full Marine

[MoMa]

As I understand, my Green Spotted Puffer (Tetraodon nigroviridis) will eventually need to be housed in full marine conditions. I know we have a bit more to go before we get there (currently juvenile, 2 inches), but I'm looking to get some information before it happens.

1. Are there any possible tankmates?
we have no problem keeping him exclusively in his own tank, but it would be nice...

2. At exactly what stage (i.e. age, size) should we be considering this, or are we better off gradually raising salinity (slowly) over time? If better off raising over time, what is a good rule of thumb for that process?

3. Marine Tank. Size? Preferred decorations? --I've checked out fishbase, but I can only find the bits about the rivers they're in early on (I'd like to keep things as natural as possible).

4. Does the diet change much? I would assume different mollusks and invertebrates inhabit the salt water they're used to.

I know we've got some time, but heck, Father Christmas just might need some ideas for us this year.


cheers,
MoMa

 

[Flumpus]

I don't believe they NEED full marine conditions. They can definitely be kept in full marine conditions, but all that is needed is an SG of 1.010 or higher.

 

[nmonks]

As Flumpus has said, GSPs don't "need" marine conditions per se, though such conditions may have certain benefits. GSPs live in estuaries and the lower parts of rivers, and are adapted to swimming between fresh and brackish water. They don't live in the sea. Since we can't give them fluctuating salinity (because that would kill the filter bacteria) we have to choose one salinity and stick with it -- an unnatural situation for these fish.

50% seawater, i.e., SG 1.012, seems to be about right, and above this the salt itself isn't doing anything useful. What does help is that at higher SGs you can use a protein skimmer and things like living rock to optimise water quality. With many puffers, high nitrates can be a problem, and protein skimmers especially are great at removing organics before they can decay into nitrate. If you can maintain good water quality without these things, then keeping a GSP at SG 1.010-1.012 is just fine. Many specimens have been kept like this, and that is certainly how they are kept at the London Aquarium.

As for tankmates, the safest approach, in a big tank at least, is to keep more than one GSP. But I've seen them housed with monos and scats as well. A lot depends on the size of the tank and the personality of the GSP in question. Some GSPs are totally peaceful, some are almost psychotic in their level of aggression, but most are in the middle there: a little nippy, certainly snappish if over-crowded, but reasonably safe with fast-moving tankmates in a large aquarium. At a high SG (1.018) I'd probably think about some of the more robust damselfish, such as Neoglyphidodon oxyodon. These fish have just the right level of aggression and speed to work well with pufferfish. They are also very hardy and easy to keep, and usually cheap because people don't always want such aggressive animals in their reef tanks.

I'd be keeping a GSP at SG 1.005 for the first couple of inches of size, and then working slowly up to SG 1.012+ between 3 and 4 inches. These fish are hardy, and aren't going to die because you adapt them to strong brackish too slowly. Killing off the filter bacteria by making too-fast a salinity change is much more serious.

As said above, they don't live in the sea, so "reef tank" decorations would be superfluous. Instead, think about an oyster reef or harbour. That's closer to what they want. Lots of rocks, perhaps with stacks of oyster, mussel, and barnacle shells. You can make an excellent substrate for these types of systems by mixing river or coral sand with equal parts of crushed mussel and oyster shell. Scatter a few snail shells on top, and the effect is very realistic.

Diet remains fixed: shelly invertebrates. Doesn't really matter what, but snails should be there for the smaller specimens, and the larger ones small whole mussels and clams that they can crack with their beaks.

Cheers,

Neale

 

[AMS]

Dave Legacy has a tank that looks very close to the natural environment of Green Spotted Puffers. Try searching in the brackish forum for his GSP tank, he has posted a few full tank shots before.

 

[MoMa]

Awesome!
Thanks for the help.

I'm realizing I didn't find any habitat bits on fishbase because I was looking for full marine! And I love the idea of the damsels when we get to that point -- it's actually what I was hoping for!

As for 1.005 for the first couple of inches...
He's currently 2" (not counting edge of tail), and being kept at 1.008-1.009. This is obviously higher than Neale's suggestion. Should I be gradually lowering this?


other bits on the tank here.
GSP, BBG, Black Molly adult, Black Molly juv., 2 Black Molly fry. 55g hex.

 

[nmonks]

He's currently 2" (not counting edge of tail), and being kept at 1.008-1.009. This is obviously higher than Neale's suggestion. Should I be gradually lowering this?
GSP, BBG, Black Molly adult, Black Molly juv., 2 Black Molly fry. 55g hex.

Don't worry about it. I'm sure he's fine. In the real world these fish have to adapt to very rapid salinity changes. We molly-coddle them a bit, though really the issue is the filter bacteria rather than the fish. All your fish should be fine at SG 1.010 - 1.012, so if your GSP happens to be one of the nice specimens (and they do exist) then leave it in their with the goby and mollies and you'll have a nice bunch of fish. Mollies especially do really well in brackish and marine water conditions.

Cheers,

Neale