# Black Mollies -- are they really that useful?



## JerseyScape

Hi,

Every so often I come across a person that raves about the usefulness of black mollies. These people claim that mollies devour algae and surface buildup. Can anybody here confirm these statements? 

If true then what kind of algae do they eat?

If they are this useful I would like to get some of these but most of the pet stores have sick ones that are barely swimming. (I guess they are sensitive?)

Thanks


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## trenac

They do pick at algae, mostly hair algae that grows on the leaves of plants. To make them efficient at being a algae eater you would severely have to underfeed them, which is not a option for me. 

As for surface scum one molly can keep a 20G tank clear of the nasty stuff. I experienced this when I removed my Molly from one tank to another, once I did the surface scum appeared within a week of moving the Molly.


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## acbaldwin

My black molly was the first fish that got me into this hobby. I've still got a few, they are fairly useful, nibble at just about any algae that hangs off of plants, nibble the junk on the substrate, are hardy, and have better personalities than most livebearers IMO. The only negative I've found is that they usually aren't that attractive if you ask me (except perhaps the sailfin variety) and may not work well in many theme tanks.
I've never had a problem with them being aggressive or nippy to any of my fish, and they leave my cherries, amano, and ghosts alone. They would probably feast on the shrimp fry, though. I gave my mollies to my bro, I wasn't about to find out the hard way.

I find swordtails to be a great addition to my planted tank, similar to the molly but more attractive and a bit smaller.


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## Faruk Gençöz

As Trena said and to my experience they eat hair algae. They do excellent job when they enter the new aquarium. A couple of days later they begin to wait for the fish food. When placed in a new aquarium they immediately begin to eat algae again in their new tank. This makes me think that they eat and deplete algae in their tank in a couple of days. When the algae they prefer is exhausted they begin to search for fish food. Whenever they are put in a new tank with fresh algae they again tend to eat algae first.


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## sayembara

No doubt about the surface skimming.... mollies clear the oily water surface.


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## matthewburk

Mine also eat BGA, and brown algae.


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## MiSo

mine ate like a pig, and only ate flakes.
never any algae, and the thing was a waste factory.


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## Faruk Gençöz

MiSo,

What kind of algae do you have in your tank? Can you post a pic? Let's see some molly and algae.


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## JerseyScape

If I get mollies I will not feed them...they will either eat surface scum, algae or DIE. :toimonst:


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## Pseud

Well... that's not very responsible of you.


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## JerseyScape

Pseud said:


> Well... that's not very responsible of you.


After reading what people wrote that Mollies eventually get used to eating fish food, I don't want to spoil them. I don't think that they'll actually die as they will probably nip at algae here and there.


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## Pseud

Oh, well that's ok then. I'm sure they'll be a picture of health.


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## pretzelb

I've had dalmation molly (and assorted platy) since I started my 29g tank. They aren't that great at cleaning but since I've had them since the start it's hard for me to say what it would be like without them. I do know that I added 2 oto's to my tank and they are cleaning up algae (mostly likely brown algae) like crazy.


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## acbaldwin

JerseyScape said:


> If I get mollies I will not feed them...they will either eat surface scum, algae or DIE. :toimonst:


...Or they'll just eat your shrimp [smilie=l: .


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## bharada

The problem I had with mollys (well, liverbearers in general) picking at algae (cladophora, in my case) is that they don't necessarily eat it all. So the remanants of what they picked at are now loose in the tank to settle and propagate elsewhere.


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## MiSo

fgencoz said:


> MiSo,
> 
> What kind of algae do you have in your tank? Can you post a pic? Let's see some molly and algae.


my black molly passed away about a month ago. never got any pictures of it or my aquarium. molly had swim bladder disease, i tried feeding it peas and adding epsom salt to the qt tank but it didnt help. 
i mostly have fuzz and staghorn algae. got a little bit of BBA but i know mollies wont touch that.

after the molly passed away, i'm noticing a bit more hair algae. maybe he was taking care of that.


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## Faruk Gençöz

Good points. Thank you and I am sorry for your black molly.


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## warr40

I have swordtails and they eat my plants i gotta move em


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## Aquaspot

Actually all mollies are good algae cleaning crew, not necessarilly just the black ones. 
They are especially good at cleaning up hair algae and other soft algae, as well as acting as live surface skimmers!


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## yildirim

Hi, I myself prefer guppies. Much smaller and nicer. I feed them very low and they are always busy picking up sth from the leaves everywhere and also the surface is crystal clear. I realy like to keep them.

YILDIRIM


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## Gumby

I've got 2 black mollies in my 125 and they keep the surface spotless. They also pick at algae all day long. One thing that my mollies do that I havent heard of is they are eating my BGA. Maybe mine are special, who knows. 

I can definately say that I'll be putting mollies in every tank I have in the future.


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## [email protected]

*mollies*

I love mollies, mine are a great clean up crew. I have green, silver, black ,orange sailfins, dailmation, black, lyre tail and a wonderful mix of each from all the breeding. The only draw back for me is they fight :axe: my bottom feeders for the algae wafers.


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## [email protected]

JerseyScape said:


> After reading what people wrote that Mollies eventually get used to eating fish food, I don't want to spoil them. I don't think that they'll actually die as they will probably nip at algae here and there.


They are very useful and interchangeable, Mollies pref is algae but even in the wild they get nutrition from eating other foods.
This was a direct quote from http://www.saltcorner.com/sections/zoo/mollies.htm
Mollies (Poeciliidae)
"There are now 'saltwater' Mollies available that are already raised in a seawater environment. They are bold micro and macroalgae grazers and make peaceful tankmates.

Many of the various molly colors seen in pet shops are due to selective breeding that emphasized certain features and may have involved several species of mollies. Available marine varieties include the Green Sailfin Molly (wild), Silver Sailfin Molly, Black Sailfin Molly, Dalmation (Mottled) Sailfin Molly, Gold Sailfin Molly, Black Sphenops, Yucatan Mollies and others. The sailfin varieties tend to get larger than most others, - three to six inches long (7.5 - 15 cm), but are quite gentle with other fish. The Yucatan mollies tend to remain small, about two inches (5 cm).

Mollies are often portrayed as a difficult fish to maintain and are commonly only kept as a freshwater fish. They are supposed to require brackish water, high temperatures, special foods and frequent treatment for fungus and other infections. However, we have found mollies to be quite easy to keep and breed in the marine environment if you keep in mind a few essential aspects such as fairly good water quality, proper nutrition, and their temperature requirements. The salt tolerance of mollies allows them to live in water ranging from completely freshwater to completely marine, which makes mollies potentially compatible with a wide range of setups. This is fairly unusual, as most fish are compatible with only freshwater, brackish water or that of only saltwater environments. This ability allows mollies to live in a variety of coastal environments.

It is a misconception that acclimation to a marine environment must be done slowly over a period of at least several days to allow their bodies time to adjust and minimize stress. This is a theory that I have documented as being false, since we have developed an acclimation method that fully and successfully changes a molly from freshwater to marine in less than 3 hours.

Also a misconception is the idea that mollies require excellent water quality. This has been proven incorrect, at least as far as marine mollies are concerned. Our studies show that mollies correctly acclimated, and especially the offspring born in a salinity of 1.022-1.023, are a very hardy fish. In fact, they are even capable of surviving the break in period of a new marine aquarium (establishment of the nitrification cycle), thereby rendering them more useful than damselfish because of their mild temperament.

Also, the presence of many known molly illnesses has not been seen in any of our marine mollies. The only case of illness was seen in one of our first mollies. This fish displayed a noted disintegration of the mouth, but after 2-3 days of being fed a diet of mysis and brine shrimp the symptoms disappeared and never returned. This problem has not been repeated because we now feed all our mollies a complete marine diet. This is not to say that marine mollies are indestructible, but suggests it may be easier to maintain healthy mollies in a good, clean marine aquarium with a balanced diet.

Mollies are often the first fish in a community tank to show signs of being affected by an unbalanced aquarium, so they could be viewed as indicator species. A common rule of thumb in the freshwater hobby was that mollies required frequent water changes. However, we have found that our mollies thrive in healthy reef aquariums, where water changes are not required that often.

Nutrition wise, plants/algae, and other type green foods are absolutely necessary for good molly health. Caulerpa prolifera seems to be the best marine algae to sustain marine mollies. A second choice would be C. mexicana.

Mollies tend to prefer a temperature around 76°F, which is a good temperature for many other marine fish and plant species. Also keep in mind that mollies, especially sailfin mollies, tend to have long fins which may invite certain species to pick on the usually gentle mollies. For this reason mollies do best in a reef environment or a nonaggressive-type fish-only tank.

Of possible interest, we had a fish recently come into our shop with Marine Ich and my molly fry began to pick it off just like a cleaner fish! I'm not sure if this is normal for mollies, as it's the first time we have even seen such behavior, - interesting though! We should add that black feeder mollies are a great source of food for many marine carnivores, and they are available either alive or frozen.

The grace and beauty of mollies should be experienced by marine aquarists. A tank with live plants and mollies is hard to beat and not that difficult to maintain>"(http://www.saltcorner.com/sections/zoo/mollies.htm)


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## jehanzeb

Can't say for sure if it's really just the Black mollies. I guess all mollies are algae eaters. I previously had gold fish and the entire aquarium had lots of algae that i had to scrub off regularly. But later on, when i replaced the goldfish with only 6 mollies in a 30gallon tank, it took them only 2-3 days to eat all the algae. This was while i was feeding them flakes daily. I havent seen algae in my tank since i started keeping mollies. 
If you want to read more about them, i came across this websites that's dedicated to Mollies. Helped me a lot while starting off with the hobby:





Mollies Fish Care


Mollies Fish Keeping Guite



mollies-fish.com


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## Michael

Welcome to APC!

This is a very old discussion--2006--so you are unlikely to hear from any of the original posters.


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## jehanzeb

Hi Mike, thanks! I guess so..


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## tiger15

All live bearer will pick on algae, but molly are most deligent. Mine will pick on algae in between meal, and don’t get lazy getting old or well fed. They aren’t as effective as sucker mouth in cleaning flat surfaces, but more effective in picking out hair algae on delicate leaves and stems. Most domesticated molly are hybrid or mutant, not my cup as my preference are wild color type. They are very dependable algae eater, and the only weakness is that they are short live. They rarely live beyond 3 year, so I start breeding them young for the next generation before they get old.


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## mistergreen

tiger15 said:


> All live bearer will pick on algae, but molly are most deligent. Mine will pick on algae in between meal, and don’t get lazy getting old or well fed. They aren’t as effective as sucker mouth in cleaning flat surfaces, but more effective in picking out hair algae on delicate leaves and stems. Most domesticated molly are hybrid or mutant, not my cup as my preference are wild color type. They are very dependable algae eater, and the only weakness is that they are short live. They rarely live beyond 3 year, so I start breeding them young for the next generation before they get old.


Nice! It's hard to find natural sailfins. How good are they at eating BBA?
I hear Poecilia velifera is a much more dedicated herbavoire than Poecilia latipinna_._


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## tiger15

mistergreen said:


> Nice! It's hard to find natural sailfins. How good are they at eating BBA?
> I hear Poecilia velifera is a much more dedicated herbavoire than Poecilia latipinna_._


I don’t know how good they are in eating bba since I don’t have any. But since they nib on leaf surfaces and edges, they target the same type of algae as SAE and will likely prevent young bba from establishing. Molly are good at eating soft algae, and established bba are likely too tough to swallow.


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