Freshwater fish in saltwater tank?
- Thread starter Sharkbait
- Start date
BoomerD
Well-Known Member
Mollies aren't actually freshwater fish, but rather brackish water. They can be acclimated quite nicely to saltwater, but of course, since this is not their natural habitat, they don't usually live as long. Many people use the s/w acclimated ones as feeder fish. Supposedly they are more nutritious than goldfish for the salt water predators.
mps9506
Well-Known Member
BoomerD said:
Ditto.
Other brackish fish sometimes seen in the FW hobby include "FW puffers", monos, scats, flounder, various gobies.
Some types of killies, and other topminnows can be acclimated to full salt.
FWIW, sailfin mollies are pretty common in the salt marshes on the east coast.
Cougra
Well-Known Member
Mollies have an amazing ability to adapt. I have seen people put them from a freshwater tank right into a fully saltwater tank and live, however I think it would be best slowly to raise the salinity over the course of a week or two. If the Mollies have been kept in a system that has a bit of salt added all the time then they can be acclimatized faster then one that has been kept in a completely salt free tank.
Not all freshwater fish can be adapted to saltwater conditions. There are primary and secondary freshwater fish. Primary freshwater fish have evolved in freshwater and as such can not handle high levels of salts in the water for long periods of time.
Secondary freshwater fish are fish that started off in the oceans and slowly moved inland. These fish tend to do better with a bit of salt in the water but still can't really adapt to full salwater conditions.
Then there are brackish water fish that can adapt to full saltwater and full freshwater conditions but still tend to do better somewhere between the two extremes. (This is where mollies fit in.)
Not all freshwater fish can be adapted to saltwater conditions. There are primary and secondary freshwater fish. Primary freshwater fish have evolved in freshwater and as such can not handle high levels of salts in the water for long periods of time.
Secondary freshwater fish are fish that started off in the oceans and slowly moved inland. These fish tend to do better with a bit of salt in the water but still can't really adapt to full salwater conditions.
Then there are brackish water fish that can adapt to full saltwater and full freshwater conditions but still tend to do better somewhere between the two extremes. (This is where mollies fit in.)
Little Luey
Active Member
I used a molly to get ammonia in to my 20gal for 3 weeks. I used the old floating the bag acclimatation, but it was a lot slower, it probably took me 3 hours to release him in the tank. This was probably over kill but i wanted to go slow. After 3 weeks he developed kind of like an air bubble on his head and I had to sacrifice him. I always wanted to try swiching a fish like this. It is also a lot less expensive since the mollie was $1.50 compared to a $10 damsel.
jmanrow
New Member
Guppies, will adapt to full strength seawater, but will not reproduce in it.
As far as adapting mollies(which breed in any salinity!) and flounder to saltwater, replacing freshwater with saltwater as a 50/50 mix adapts them without any ill effects in two days.
This also prevents a possible pH shock.
As far as adapting mollies(which breed in any salinity!) and flounder to saltwater, replacing freshwater with saltwater as a 50/50 mix adapts them without any ill effects in two days.
This also prevents a possible pH shock.
reefjitsu
Active Member
Most of the common livebearers in the FW trade can live in fresh for a while (as Witt said, natural forms do better than captive breeds). As for mollies, Black mollies do best in water with a little salt but not quite brackish. As for Sailfin mollies, they seem to do alright in any water. I catch them from salt marshes in full strength sea water down on the Gulf. You can keep and breed them in saltwater, thus making them the best choice for live feeders that you can raise yourself. FW fish that have been acclimated to salt are not as good. The fish needs to be raised in SW and eating marine foods in order to achieve maximum nutrition for our marine fish.
Scats and monos are probably the best bet for a "FW" fish that can be kept in a reef. I have been seeing alot of "FW" puffers kept in reefs lately (curiously after an online mag featured a pic with one). This is ok for some species for awhile, but most will not live their full lifespans like that. Also, beware that some puffers are entirely FW and will die if you try this, so do your research. There are actualyl quite alot of fish that can make these transitions, but they are not commonly available in the trade.
http://www.reefsanctuary.com/forums/general-reef-aquarium-discussion/10008-saltwater-frogs.html
Scats and monos are probably the best bet for a "FW" fish that can be kept in a reef. I have been seeing alot of "FW" puffers kept in reefs lately (curiously after an online mag featured a pic with one). This is ok for some species for awhile, but most will not live their full lifespans like that. Also, beware that some puffers are entirely FW and will die if you try this, so do your research. There are actualyl quite alot of fish that can make these transitions, but they are not commonly available in the trade.
http://www.reefsanctuary.com/forums/general-reef-aquarium-discussion/10008-saltwater-frogs.html
That is false about guppies, they will adapt and they DO reproduce in it. Many people including me sump them, and they reproduce creating more food for the tank. I also have 10 in a 10gal full reef system and I have watched them give birth.