Are there any species of saltwater goodeids? I know that almost all species of livebearers can be converted to salt water but I have never heard of anyone trying to do it with goodeids. Is this only because many of the species are endangered or are they a rarity that doesn't have the ability to adapt to salt water?

No species of fresh water livebearer can be converted over to salt water. Mollys naturally live in a brackish environment, and most goodeids can be cultured to live in a brackish environment as well, but if there is too much salt in the water they will die. Im thinking that you actually mean brackish (lightly salted water), rather than marine saltwater. I think unless you want brackish fish, you'd be better off keeping the livbearers in fresh water as thats pretty much what they've been raised to live in.

Not quite true. Guppies and mollies can be adapted to marine conditions, and mollies occur in marine waters in the wild quite commonly. There is a good argument for calling mollies generally brackish water fish, not freshwater ones. Guppies need very slow and careful adaptation, but they will live and breed in seawater, and wild populations can be found in brackish and salt water, particularly on the Caribbean islands. Guppies have been kept in micro-reef aquaria, as small, colourful alternatives to standard marine fish.

Mosquitofish of various kinds (Gambusia spp.) are very common in brackish and salt water, though aquarists hardly ever keep them. Pike livebearers are also found in seawater, but again, these are fish for specialists. There are lots of species of Poecilia that aquarists don't keep at all that do occur in brackish or salt water (e.g. Poecillia gilli).

Virtually all the other livebearers can be adapted to quite brackish water: platies and swordtails will take 25% seawater, if adjusted to it slowly and carefully. I don't recommend this, as they aren't brackish water fish, but in terms of physiology, they can cope just fine.

I'm not sure about goodeids. There certainly are some, like Ameca splendens, that do well in slightly brackish (SG <1.005) but I can't think of any that need (or like) mid to high salinities.

Cheers,

Neale

Wow really? I didn't think guppies could live in marine conditions.

Yep, it can be done. It isn't easy though, and needs to be done very carefully, with the fish adapted over several weeks. If you don't adjust them carefully, they simply die at about 25% seawater. For that reaosn, I don't recommend trying. But it is certainly possible, and some marine retailers trade "saltwater guppies" as feeder fish for marine predators like lionfish and morays.

I am told Endlers will tolerate salt water too. With both Endlers and guppies, marine conditions aren't particular natural, and the reason they tolerate salt water is that they evolved from marine fish. It's the same reason why so many cichlids can be adapted to 50%-100% seawater, even species that are primarily freshwater inhabitants.

With mollies, you can pretty much take them from fresh to salt within a hour or two.

Cheers,

Neale

Lol thats crazy, probably more trouble than its worth, so i wont try, but its definately got me thinking.

Wow, really? I didn't know that. Like which ones?

See here for a list of naturally brackish water cichlids that I'm aware of:

http://www.fishforums.net/index.php?s=&sho...dpost&p=1200746

Pretty much all non-specialist cichlids, like tilapias, will tolerate low salinities. Specialists (e.g. blackwater species such as angels, or Rift Valley species) do not tolerate salt well, if at all.

Cheers,

Neale

You are a very helpful person. You are an author aren't you? They should make you a moderator

Can you tell me any peaceful freshwater fish that I could possibly (without harming them) put in the reef tank? Somehow, I feel unsure of putting any Tilapias or Nandposis in there but otherwise it sounds like a neat undertaking.

Oops, topic hijacking!
-Lynden

This post has been edited by Lynden: Aug 23 2006, 01:25 AM

You're right... generally cichlids are a bad idea in marine aquaria, because they're so aggressive and disruptive. So even though there is a long list of cichlids that will tolerate 25% to 100% seawater, there's no real need to adapt them to such conditions. You may as well keep them in freshwater so it will cheaper to do the water changes.

On the other hand, if you already have a mid to high-end brackish water aquarium, adding things like Sarotherodon melanotheron and Cichlasoma urophthalmus could be fun. The former is fairly peaceful, but the latter has to be among the meanest cichlids known to man (which is saying something!).

Among the more suitable fish, mollies and guppies are both widely used in marine aquaria. Black mollies especially work nicely as algae eaters, and the batches of fry produce a nice snack for reef fish, particularly things like seahorses. I've used black mollies to mature marine aquaria. Adapting mollies to seawater takes an hour or two, tops. Guppies are more tricky, and need to be adapted over several weeks. You can buy "marine guppies", which are (apparently) produced by some people as feeder fish for things like snappers and groupers. There are several other livebearers that live happily in salt water but they are not so commonly seen, such as giant sailfin mollies, pike livebearers, and various obscure (in the trade at least) species of Poecilia.

Most of the brackish water fish can be adapted to marine conditions, though this may require some research on your behalf to identify correctly which species are traded in your area. Scats and monos obviously do well, but their use in reef tanks is probably limited. The purple spaghetti eel, Moringua raitaborua on the other hand would make a neat miniature moray eel (it gets to 40 cm and only eats tiny invertebrates). There are various gobies that could be kept in salt water, too. A shop near me has some brackish to salt water halfbeaks (around 20 cm long) that would look amazing in a reef tank!

Cheers,

Neale

Interesting stuff Neale. never knew that at all. getting our first marine tank in a couple of weeks, on't be stocking guppy's as quite frankly there's many more interesting marine fish.... might be interesting to do a little experiment with one of the spare tanks though, build some up slowly to it. hmmmmm

Indeed, but then the saltwater livebearers seem to be used in two specific cases. Firstly to mature tanks. Mollies are nitrite tolerant and good algae eaters, so they're ideal for maturing aquaria. The second use is guppies in micro-reef tanks, where one or two male guppies would be much nicer (and safer) than a damselfish or some other hardy but larger marine.

There are a few brackish fish that do hold their own in big marine, usually fish-only, tanks. The silver scat is one; it's a beautiful fish. The other, oddly enough, is the shark catfish. I've seen public aquaria with Arius spp. in reef tanks. While they will eat shrimps and crabs, they're fine with corals, anemones, starfish, etc. For anyone after a substitute for a shark, they come pretty close.

What's more of a surprise for marine aquarists is that a good many of their fish are brackish water as well. Some of the puffers, sharp-nose puffers, snappers, grunts, damselfish, and batfish, for example. They can't be adapted to freshwater (with a few exceptions) but at SG 1.010-1.015 depending on the species they can be kept in brackish water tanks just fine. The boundary between fresh and salt water fishkeeping is obvious, but in the real world, these habitats blend into one another.

Cheers,

Neale

Your knowledge never fails to amaze me! Just for research purposes, are there any damselfish that can be adapted to freshwater?

-Lynden

This post has been edited by Lynden: Aug 23 2006, 08:12 PM

No goodeieads need salt.

most people just dont wanna take the risk this is a rare fish