Hyposalinity QT questions.

[Chibils]

I am in the process of setting up a 30G long with the intent to make it a new QT. Halfway across (18"), I will place a 6" tall baffle, fill one side with fiji mud, and plant mangroves in it. The salinity is going to be kept at brackish levels - 1.009 to 1.011. The mangroves are mostly for aesthetic purposes, but the roots provide good cover for fish. According to Julian Sprung, "they can be grown perfectly
well in pure freshwater, even soft water. They are quite hardy and adaptable!" So a habitat between salt- and freshwater would do them quite well, as if often their home.

Now here comes my next question:
I work for a pet store. I am capable of getting as many Uca spp. (fiddler crabs) as I need. We also have two dwarf puffers that I would like to put in there, as their needs aren't really met. Would that be a mistake waiting to happen (as far as the puffers go, at least)? They stay relatively small and, if need be, I can screen them off before fish are introduced to the qt.

Another question:
How do you acclimate a fish from nsw levels (1.023-1.026) to hyposaline levels (1.009-1.011)? I don't want to screw that part up, as it would make the tank largely pointless (it IS a qt...). This is especially important for me now as I think about acclimating the crabs, who come in from a freshwater facility.

Sprung, regarding Uca sp. crabs:
"With tidal change it would be possible to house some of the nerite and littorinid snails that graze algae off the Mangrove's roots, and possibly Sesarma crabs, or Uca species a.k.a. 'Fiddler crabs.'"

 

[JHemdal]

Scott,

Just a couple observations - the last time I tried Uca in our mangrove exhibit we had them out all over the building. They are VERY difficult to contain.
Have you seen Charles Delbeek's recent article in AFM where he refutes the ability of Mangroves to great a net export of nutirents from the system? I've been saying that for years, but not everyone listened(grin).
It seems to me that you are going for a biotope tank rather than a quarantine tank - what if you need to add medications?

Jay

 

[Chibils]

Jay -

I'm well aware that mangroves perform poorly in nutrient export due to their slow growth. But as you stated, I'm aiming for an ecosystem - that's the whole reason I went into reefs instead of FO or even FOWLR. I have a 10G HT (my old QT) should I need to dose medicines. I'm well aware that Uca are master escape artists, but I can put pond netting (1/4") up, since I have a 6x14' sheet for a 4x1.5' tank.

Beyond that, would the crabs or puffers be a poor choice? Am I asking for a disaster by putting semi-aggressive brackish fish in a QT? I feel like I am, but I really want them.


And also, how do you recommend acclimating a fish down by nearly 25ppt salt?

 

[JHemdal]

Chilbils,

The puffers and crabs of course won't be compatible with one another - if nothing else the puffers will take out their eyes. I would also worry that the puffers would be fin-nippers on new fish, depends on the species though.
Generally, the S.G. that fish are being kept in can be lowered quite quickly - certainly halving the salinity in 24h is fine. Now raising it up - totally different situation - give it a full seven days to got from 1.0215 to 1.025.

Jay

 

[Chibils]

I knew the puffers were a bad idea, but they're so cute.

So get a biiiig bucket, and drip acclimate for 24 hours or so until the sg is at the same level as the qt? I hate to think of what that would do to the water level in the tank. O_O

 

[JHemdal]

Scott,

See - that is exactly why I am not advocating multiple use of a quarantine tank as a biotope as well. The normal way to do this is move the fish into the Q tank at regular salinity, and then bring the Q tank down to hypo. It would be too rough on the fish to do this in a bucket. And then, how are you going to conclude the hypo? In a dedicated quarantine tank, you just bring the salinity up gradually over a week's time - but you can't easily do that if you have all these other critters in there....I would strongly suggest you go with a dedicated Q tank from the outset.

Jay

 

[Chibils]

Could I do this whole process at normal salinity? Crabs, mangroves, and new fish? Messing with salinity sounds like way too much trouble, and moving to the HT about ten feet away for treatments would be much easier. Hypo just seemed like such a great idea -- fiddlers' natural habitat, less Mg supplementing for the mangroves, and all the benefits of hyposaline quarantining. At least at 1.024-1.026 I would have a clean-up crew instead of having to siphon uneaten food out every feeding, an interesting pseudo-display, and mangroves, one of my passions.