Mollies

[Debbie_19]

Recently my mum purchased two mollies for her tank, one dalmation one and silver one. And I fell in love with them straight away, think they are very cute. I have a smallish tank at the moment which is doing well and I was hoping to upgrade to a bigger tank soon. I was going to get a tank and put a few kinds of different fish in but thought about mabey having one with just mollies and trying to breed them.

Are these easy to breed and are they quite easy fish to keep? It is a good idea just to keep mollies or would it be better to have different types of fish in there. Hopefully getting a tank around 100l.x

 

[theotheragentm]

Read the sticky in this forums about brackish water and Mollies. That limits the number of types of fish you can keep with them. Mollies CAN be kept in freshwater, but water has to be kept immaculately clean as fungus, fin rot, and ich can occur if not kept well.

Mollies will breed like crazy. It's what they do in nature. You should keep a ratio of 3:1 females to males for the first male and 2:1 for every additional male. You may want to consider that with your tank size currently.

Also, you will have lots and lots of fry very quickly if you have male and female Mollies, another thing to consider with tank size. Mollies will eat their fry, whether they are their own or a batch from another fish. Some will survive almost every time as a few find places to hide, and some just never get eaten even when in the open.

Mollies are peaceful fish in general, but they may become territorial when ready to give birth as they want space. If your tank is small, I would say to not go with freshwater as water conditions are much harder to maintain on smaller tanks. That leaves you with brackish fish to select for your tankmates.

 

[Debbie_19]

Read the sticky in this forums about brackish water and Mollies. That limits the number of types of fish you can keep with them. Mollies CAN be kept in freshwater, but water has to be kept immaculately clean as fungus, fin rot, and ich can occur if not kept well.

Mollies will breed like crazy. It's what they do in nature. You should keep a ratio of 3:1 females to males for the first male and 2:1 for every additional male. You may want to consider that with your tank size currently.

Also, you will have lots and lots of fry very quickly if you have male and female Mollies, another thing to consider with tank size. Mollies will eat their fry, whether they are their own or a batch from another fish. Some will survive almost every time as a few find places to hide, and some just never get eaten even when in the open.

Mollies are peaceful fish in general, but they may become territorial when ready to give birth as they want space. If your tank is small, I would say to not go with freshwater as water conditions are much harder to maintain on smaller tanks. That leaves you with brackish fish to select for your tankmates.

Thanks for the reply, also just another quick question, the one that my mum recently purchased is rather fat looking and the other isn't, could this mean that one is already pregnant.

 

[theotheragentm]

It's quite common to get a livebearer from a fish store and already have them pregnant. A little fat can just be bloating. Pregnant fat is unmistakable in my experience. From behind the fish's abdomen will look almost rectangular.

 

[nmonks]

Just going to second what theotheragentm has said: when keeping mollies, your life is massively easier if you add marine salt mix to the aquarium (3-4 grammes per litre will work great).

The current theory is that the key factor is nitrate (not just nitrite). Mollies seem to be orders of magnitude more sensitive to nitrate than other livebearers. If kept in pristine freshwater aquaria where the nitrates are very low (essentially zero) then they seem to do okay. It's when moved into community tanks where the nitrates are high (i.e., 20 mg/l upwards) that the problem with finrot, fungus, etc. set in.

Salt dramatically reduces the toxicity of nitrate, and this is one reason it has been used as a "tonic". In brackish water, mollies effectively become "immune" to nitrate, and can be kept even under relatively poor water conditions.

Anyway, this theory explains how mollies become established in freshwaters around the world (e.g., ponds and lakes in Texas and California) yet often do badly in freshwater aquaria. Natural waters rarely have high nitrates, but most aquaria do have high nitrates.

The traditional explanation -- which I certainly believe is a factor if not the only factor -- is that mollies have brackish water ancestors, and wild mollies at least occur very commonly in brackish water.

Cheers, Neale

 

[Debbie_19]

Just going to second what theotheragentm has said: when keeping mollies, your life is massively easier if you add marine salt mix to the aquarium (3-4 grammes per litre will work great).

The current theory is that the key factor is nitrate (not just nitrite). Mollies seem to be orders of magnitude more sensitive to nitrate than other livebearers. If kept in pristine freshwater aquaria where the nitrates are very low (essentially zero) then they seem to do okay. It's when moved into community tanks where the nitrates are high (i.e., 20 mg/l upwards) that the problem with finrot, fungus, etc. set in.

Salt dramatically reduces the toxicity of nitrate, and this is one reason it has been used as a "tonic". In brackish water, mollies effectively become "immune" to nitrate, and can be kept even under relatively poor water conditions.

Anyway, this theory explains how mollies become established in freshwaters around the world (e.g., ponds and lakes in Texas and California) yet often do badly in freshwater aquaria. Natural waters rarely have high nitrates, but most aquaria do have high nitrates.

The traditional explanation -- which I certainly believe is a factor if not the only factor -- is that mollies have brackish water ancestors, and wild mollies at least occur very commonly in brackish water.

Cheers, Neale

Thank you for all your comments. Is there any other fish that will do well in slightly salted water that i could put in with these fish. Also I am planning to get a tank about 80l, how many would i be able to purchase? I was hoping to get about 150l tank but it is in my bedroom in a upper floor so don't want to risk the weight.

 

[nmonks]

Oh my, there are dozens and dozens of species suitable for a brackish water aquarium that would get along great with mollies: orange chromides, kribensis, bumblebee gobies, knight gobies, violet gobies, clay gobies, glassfish, wrestling halfbeaks, guppies, butterfly-goby waspfish (though this would eat the babies!), spaghetti eels, etc., etc. Heavens, you can even keep mollies in a marine reef tank with seahorses!

Come visit the brackish forum elsewhere on this site. Have a browse of the pinned topics to find out about brackish water fishes and plants. Buy my book! Or maybe just read the FAQ (link below).

Cheers, Neale

Is there any other fish that will do well in slightly salted water that i could put in with these fish. Also I am planning to get a tank about 80l, how many would i be able to purchase? I was hoping to get about 150l tank but it is in my bedroom in a upper floor so don't want to risk the weight.