Experiences With Guppies In High Salinity Water

[Revision17]

I was reading the book "Brackish-Water Fishes" by Neale Monks, and it mentions that guppies can be adapted to full strength marine conditions with care. The wikipedia article onGuppies says:

The guppy prefers a hard water aquarium and can withstand levels of salinity up to 150% that of normal sea water.[7], which has led to them being occasionally included in marine tropical community tanks, as well as in freshwater tropical tanks.

Searching on the internet, I find a few journal threads with people adapting them to marine conditions to use as feeder fish but without great detail. Usually only saying that they increased salinity by a small amount and they're still doing fine.

What have your experiences been with gupppies in high salinity water?

 

[nmonks]

The art, such as it is, to acclimating guppies to saltwater conditions is to go slowly. They aren't really "brackish water fishes" in the sense of being fish able to swim between freshwater and saltwater environments. Mollies, by contrast, can be almost dumped into seawater from a freshwater tank without problems.

Anyway, it takes a good couple of months or so to safely acclimate guppies to marine conditions. You're aiming to go up a notch or two on the SG scale with each weekly water change (i.e., SG 1.005 to 1.006, 1.006 to 1.007, and so on). Acclimating guppies to low end brackish (SG 1.005 or less) can be done in a couple hours using the drip method.

Now, here's the other critical thing: Inbreeding has been proven to reduce salt tolerance in guppies (Chiyokubu et al. 1998). Wild guppies are fine, and feeder guppies are fine. But your fancy guppies may not be. If you can only get fancy guppies, then cross-breeding two completely different strains apparently fixes this problem (again, Chiyokubu et al. 1998).

Almost all the stories about people's guppies dying in brackish or marine conditions come down to either going to fast or using inbred fancy guppies.

Cheers, Neale

Chiyokubu T., Shikano T., Nakajima M., and Y. Fujio. 1998. Genetic features of salinity tolerance in wild and domestic guppies (Poecilia reticulata). Aquaculture. 167: 339-348.

 

[Revision17]

Well, I suppose replies can't get any better than when the come from the author of my book. I think I'm going to start adapting a few dozen of my couple hundred guppy fry (I think after the next guppy gives birth, the rest of the fry will have to survive on their own with adults or become tiger barb food, as I don't have the money to house them) to salt water from now until februaryish, when I can finally get another tank (which will be high brackish to marine, not sure yet).

Thanks for your time and giving a definitive reply, with a reference (which I am reading at this moment).

 

[el_vulture619]

I have used feeder guppies for my waspfish. it is currently at 1.010-15 depending on the water change. The guppies seem to do fine! The longest I have seen one live was 2 weeks. Then it was eaten. I am going to set up a small tank for them soon, so I can try to get a constant CLEAN supply of them.

They adjust pretty quickly to the conditions. From the store they go from cold FW to warm BW in a half hour or more. Some do die but I am sure those are the weaker fish.

 

[el_vulture619]

I have set up a 10 gallon for raising feeder guppies in BW. I have a sponge filter inside and seeded it with filter gunk from my main BW tank. I let it run for a week before adding the guppies.The sal is now 1.010 and I top off with RO water. The temp is set to 70-72 degrees. There is also a molly in the tank. I feed them marine flake.

I put in 40 guppies, many of them died with in the first week, and a few are dying every day, however I still have 20+ and they seem ok, until next morning What can I do to increase the survival rate? Most of them are small guppies, none are close to adult size. I think I will place a bag of carbon it the tank, but if no water is flowing though it how will it help.....?

Can it be the mollie is harasing them? I know it is a pretty aggresive mollie, it used to chase my GSPs around!

I take pout the dead guppies and feed them to my bubble tip nem in my 10g nano, it LOVES them! At least I am getting some use out of them.