Compatibility of a Molly

starypotter · Aug 7, 2018

Hi everyone,
I'm considering getting a black molly in part because of the canary in the coal mine in a tank where I got some of the rock from an established tank where I'm not 100% confident that it's disease free. But I have no idea what their compatibility will be like for the rest of the stocking. I've been figuring things out and trying to come up with my stocking list with the chart from LiveAquaria but I don't know where a molly would fall in that.

75 gallon tank. My main 'likes' are gobies, blennies, dragonets, hopefully a tang, maybe some wrasses or anthias. That's not a list just some of the things I'd like in my mixed reef, probably forgetting some.
I currently have in QT a pair of clowns, a kaudern's cardinal, and a neon goby.

Bob Loblaw · Aug 7, 2018

I have a pair in my 300 for the same reason. They never go deeper than an inch or two from the surface as they can’t handle the flow and are ignored by all inhabitants.

dede · Aug 8, 2018

I did the same thing, I had added some rock and fish that I just observed and wanted to add some Mollies to test the tank. My purple tang and anthias proceeded to tear apart the mollies so I had to put them in a breeders box. They ended up passing but I think it was a combo of high flow and not acclimating them slowly enough.

I was able to get one molly to live in a quarantine tank that I had just an air bubbler, heater and some live rock. I used this tank as the first step in testing new fish before putting them through ttm. I think this one survived because I had the salinity much lower for new fish coming in from the fish stores. Molly never bothered anyone in quarantine.

One thing I would be careful of is something Humblefish discovered was that mollies can carry an intestinal parasite/worm that is very resilient to treatment and it might be possible it can be passed to saltwater fish. Check out his thread on the subject.

There is just no easy way of insuring your tank and fish are ich/velvet free it seems. It is the one thing that keeps me from adding new stuff because I just don't want to deal with setting up the quarantine tanks.

eatbreakfast · Aug 8, 2018

I have found flow to be the biggest issue for mollies, much more so than any other fish.

starypotter · Aug 8, 2018

dede said:
I did the same thing, I had added some rock and fish that I just observed and wanted to add some Mollies to test the tank. My purple tang and anthias proceeded to tear apart the mollies so I had to put them in a breeders box. They ended up passing but I think it was a combo of high flow and not acclimating them slowly enough.

I was able to get one molly to live in a quarantine tank that I had just an air bubbler, heater and some live rock. I used this tank as the first step in testing new fish before putting them through ttm. I think this one survived because I had the salinity much lower for new fish coming in from the fish stores. Molly never bothered anyone in quarantine.

One thing I would be careful of is something Humblefish discovered was that mollies can carry an intestinal parasite/worm that is very resilient to treatment and it might be possible it can be passed to saltwater fish. Check out his thread on the subject.

There is just no easy way of insuring your tank and fish are ich/velvet free it seems. It is the one thing that keeps me from adding new stuff because I just don't want to deal with setting up the quarantine tanks.

Oh that’s good to know, I saw the molly suggestion when looking through HumbleFish’s articles about QT and disease but I must have missed that part... I might just skip out then. I wouldn’t want it to not have a good time in my tank because of the flow and if it might not be the perfect canary then it doesn’t seem worth it to me.

Halal Hotdog · Aug 8, 2018

I have kept mollies in a reef tank. Absolutely agree about the flow. The other issue is IMO acclimating them is not a concrete science. Some make it and some don't. Unfortunately because of that it is hard to know if they died of disease or because they did not acclimate to saltwater. For whatever reason females have always acclimated better than the males for me.

Hermie · Jan 3, 2019

Halal Hotdog said:
I have kept mollies in a reef tank. Absolutely agree about the flow. The other issue is IMO acclimating them is not a concrete science. Some make it and some don't. Unfortunately because of that it is hard to know if they died of disease or because they did not acclimate to saltwater. For whatever reason females have always acclimated better than the males for me.

The thing about most mollies is that they are often hybridized with various FW poecilia to get their colors... so their DNA is not pure Sailfin or "euryhaline," now that's only a theory but it makes sense to me... The other thing is that FW mollies do need more than "dropping in" to saltwater conditions, even drip acclimation over hours can result in high mortality (30 to 40%). They really need more like multiple days to weeks for acclimation...

http://lifes.nchu.edu.tw/Pic/Writings/13764965760677(1).pdf

Waters · Jan 3, 2019

I never really understood the desire to add freshwater mollies to a SW tank......I understand they eat algae and are small but there are better alternatives that are full saltwater and can handle the reef environment....aren't there lol? Not being combative.....just curious....maybe I am missing out?? I got out of freshwater to get away from the bland looking fish lol.