Tank Size for gold dust mollies

[Rollxr]

Hi everyone, I have a 20 gallon tank, and I was wondering if I could have 5 gold dust mollies and 5 platies in 20 gallon? This is my tank fir reference, rn I have 1 male molly and 2 female platiesx

 

[Byron]

The present fish in the 20g may not seem much, but they will grow. I believe this variety can attain 3 inches for males and 4 inches for females. @emeraldking will know. I would think at minimum a 30g tank, preferably larger for a group.

 

[emeraldking]

With the current number of stocking of these species, it will be fine. But as already stated, they can grow bigger than their current size. And with both genders, take future fry in consideration.

 

[Rollxr]

The present fish in the 20g may not seem much, but they will grow. I believe this variety can attain 3 inches for males and 4 inches for females. @emeraldking will know. I would think at minimum a 30g tank, preferably larger for a group.

I don’t want to keep a group, just 1 male Molly and 3 female mollies, so 4 mollies in total. Can the 20 gallon tank limit their lifespan!?

 

[Rollxr]

With the current number of stocking of these species, it will be fine. But as already stated, they can grow bigger than their current size. And with both genders, take future fry in consideration.

Well you see, this isn’t my current stocking. I want to add 2 more platies and 3 more mollies. Is that stocking fine? So it’s 4 mollies, 1 male molly and 3 female mollies. And it’s 4 platies also, so 1 male platy and 3 female platies. So 4 mollies and 4 platies, will they be fine in my 20 gallon?

 

[Rollxr]

With the current number of stocking of these species, it will be fine. But as already stated, they can grow bigger than their current size. And with both genders, take future fry in consideration.

I wanted to let you know that, the molly in the picture, i have had him in a 10 gallon tank for at least a year one(May 2021), and I just upgraded to this current 20 gallon tank which you see currently right now. I wrote this as a side note

 

[Byron]

@emeraldking and I are on the same page here. The tank is OK now with what is in it, but these fish will if healthy grow to need a larger tank. Adding any more is just compounding that issue.

And, what in the world do you intend doing with the dozens of platy and molly fry every month? They are not likely to all get eaten. This is why many keep male only tanks of livebearers.

 

[AdoraBelle Dearheart]

I don’t want to keep a group, just 1 male Molly and 3 female mollies, so 4 mollies in total. Can the 20 gallon tank limit their lifespan!?

These fish are livebearers. The female mollies and platies will churn out fry at a rate and amount that will make your head spin, every month. Do some reading up on how they breed and produce fry, check out some youtube videos maybe, and give serious consideration to what you would do with all the fry, whether you could handle raising them all, where you'd put them all while raising them, and whether any local stores near you would be willing to take the offspring off your hands, since you'd have a lot, often, and not all stores will take them.

Also bear in mind that females are often mated before you get them, and can store sperm packets for a year or more and keep producing fry even without a male around, so female only doesn't resolve the issue, and parents don't always eat the fry.

It's possible, and fun to raise livebearer fry! But worth answering the above questions first, before you have a stock of male and female livebearers and a tank full to bursting with adults and offspring!

I personally wouldn't keep mollies in less than 30g, because I've seen first hand how large they can get when given the space and time to do so, and being short finned and active, they're strong swimmers. But people do keep them in 20g.

 

[Rollxr]

These fish are livebearers. The female mollies and platies will churn out fry at a rate and amount that will make your head spin, every month. Do some reading up on how they breed and produce fry, check out some youtube videos maybe, and give serious consideration to what you would do with all the fry, whether you could handle raising them all, where you'd put them all while raising them, and whether any local stores near you would be willing to take the offspring off your hands, since you'd have a lot, often, and not all stores will take them.

Also bear in mind that females are often mated before you get them, and can store sperm packets for a year or more and keep producing fry even without a male around, so female only doesn't resolve the issue, and parents don't always eat the fry.

It's possible, and fun to raise livebearer fry! But worth answering the above questions first, before you have a stock of male and female livebearers and a tank full to bursting with adults and offspring!

I personally wouldn't keep mollies in less than 30g, because I've seen first hand how large they can get when given the space and time to do so, and being short finned and active, they're strong swimmers. But people do keep them in 20g.

So, are you saying 20 gallons is basically small because of the reproduction processs. But excluding the babies, can mollies still be in a 20 gallon?

 

[AdoraBelle Dearheart]

So, are you saying 20 gallons is basically small because of the reproduction processs. But excluding the babies, can mollies still be in a 20 gallon?

If you get females, you can't exclude the possibilities of babies.

As I said, some people might keep a few mollies in a 20g, but I personally wouldn't, because I've seen my mollies reach the ages of 7-8, and a good four inches in size.
This is a tank I inherited - those black and silver mollies were the original trio he got, that were 6-7 years old here, and produced literally hundreds of fry in their time. This is in a 57g tank, and they used the whole tank. See the gold dust molly on the left there? That's a young adult, likely around the same size as you have now. These older black and silver mollies are hybrids of different molly types, but gold dust mollies ARE one of the large species of molly, and should be able to reach 4-5 inches, like my giant black and silver sailfin hybrids.

If they have the space, care and quality diet to do so...

Sorry for blurry photo, but again, you can compare the size of adult fish that have been allowed to grow and attain size over the years, compared to the young adults that have come from a store/hobbyists, like the gold dust and lemon molly, and adult platies.

Size compared to the adult lemon yellow mollies, bronze cory, platies... that blue platy was a large female too, compared to most female platies, she was a chonker. Still dwarfed by the large black and silvers.

Again, since they're strong, active swimmers with short fins, and can attain a really good age and size with the proper care, then no, I personally wouldn't keep them long term in a 20g, because I've seen how well they can do when given the space and time to grow.

If you want to keep livebearers of any sort, you have to be prepared for the breeding issues, which usually means multiple tanks. If you have a 20g and don't want to go larger, can't manage multiple tanks, and would rather not/can't rehome tons of fry, I'd urge you to reconsider your stocking. There are soooo many fish that would be fine in a 20g for a lifetime, that also wouldn't be producing 30 odd fry or more ever month. Why not explore your options and make a thread for suggestions, before committing to livebearers? Because cramming too many fish into too small a box leads to disaster sooner or later.

If you want to keep the male molly because you've understandable become attached, and you're okay with breeding/raising the fry possibly in another tank, and rehoming them all, then I would cut your stocking plan down a lot. Keep the male molly and get two female gold dust. Stick to a trio only while it's a 20g.Return or rehome the female platies - you'll have your hands and tank full with molly fry even with just a trio of mollies. Don't add platy fry to the mix as well, especially when you're new to this! The 20g will be okay with a young trio of mollies, if you're prepared for other tanks(s) to handle all the fry, and even more so if you're prepared to upgrade the tank size as the mollies grow. Really look at these photos and think about the size they can reach, and the age, with the right space and care, and ask yourself if you're able and willing to provide that, before getting more fish.

If you're not sure, then making a thread for stocking suggestions for a 20g, or searching the forums for other previous threads where people asked that, will show you many fish that can work out brilliantly in 20g, without overwhelming you with fry every month!

 

[Rollxr]

If you get females, you can't exclude the possibilities of babies.

As I said, some people might keep a few mollies in a 20g, but I personally wouldn't, because I've seen my mollies reach the ages of 7-8, and a good four inches in size.
This is a tank I inherited - those black and silver mollies were the original trio he got, that were 6-7 years old here, and produced literally hundreds of fry in their time. This is in a 57g tank, and they used the whole tank. See the gold dust molly on the left there? That's a young adult, likely around the same size as you have now. These older black and silver mollies are hybrids of different molly types, but gold dust mollies ARE one of the large species of molly, and should be able to reach 4-5 inches, like my giant black and silver sailfin hybrids.

If they have the space, care and quality diet to do so...
View attachment 303984


Sorry for blurry photo, but again, you can compare the size of adult fish that have been allowed to grow and attain size over the years, compared to the young adults that have come from a store/hobbyists, like the gold dust and lemon molly, and adult platies.
View attachment 303981


Size compared to the adult lemon yellow mollies, bronze cory, platies... that blue platy was a large female too, compared to most female platies, she was a chonker. Still dwarfed by the large black and silvers.
View attachment 303982


Again, since they're strong, active swimmers with short fins, and can attain a really good age and size with the proper care, then no, I personally wouldn't keep them long term in a 20g, because I've seen how well they can do when given the space and time to grow.

If you want to keep livebearers of any sort, you have to be prepared for the breeding issues, which usually means multiple tanks. If you have a 20g and don't want to go larger, can't manage multiple tanks, and would rather not/can't rehome tons of fry, I'd urge you to reconsider your stocking. There are soooo many fish that would be fine in a 20g for a lifetime, that also wouldn't be producing 30 odd fry or more ever month. Why not explore your options and make a thread for suggestions, before committing to livebearers? Because cramming too many fish into too small a box leads to disaster sooner or later.

If you want to keep the male molly because you've understandable become attached, and you're okay with breeding/raising the fry possibly in another tank, and rehoming them all, then I would cut your stocking plan down a lot. Keep the male molly and get two female gold dust. Stick to a trio only while it's a 20g.Return or rehome the female platies - you'll have your hands and tank full with molly fry even with just a trio of mollies. Don't add platy fry to the mix as well, especially when you're new to this! The 20g will be okay with a young trio of mollies, if you're prepared for other tanks(s) to handle all the fry, and even more so if you're prepared to upgrade the tank size as the mollies grow. Really look at these photos and think about the size they can reach, and the age, with the right space and care, and ask yourself if you're able and willing to provide that, before getting more fish.

If you're not sure, then making a thread for stocking suggestions for a 20g, or searching the forums for other previous threads where people asked that, will show you many fish that can work out brilliantly in 20g, without overwhelming you with fry every month!

So I can have a trio of mollies, but I still can’t have 3 platies? Just 2 female platies, 1 male platy. And 2 female mollies, and 1 male molly.

 

[betta4ever!]

So I can have a trio of mollies, but I still can’t have 3 platies? Just 2 female platies, 1 male platy. And 2 female mollies, and 1 male molly.

I think your question has already been answered above... Your choise if you follow it or not.

 

[Byron]

So, are you saying 20 gallons is basically small because of the reproduction processs. But excluding the babies, can mollies still be in a 20 gallon?

I'm not sure why the answer to this question keeps getting missed because three or four of us have stated it, but that's OK. The 20g is "OK" for the fish now in it while they are still small, but it is not suitable for the present fish as they grow. And hopefully they will, if healthy. Mollies at 3-4 inches in this tank is a lot of impact on the biology, even ignoring the physical space.

 

[AdoraBelle Dearheart]

So I can have a trio of mollies, but I still can’t have 3 platies? Just 2 female platies, 1 male platy. And 2 female mollies, and 1 male molly.

Not saying you can't - it's your choice! Just a heads up that the adults can get very large, given the change, and that the amount of fry can quicky become overwhelming. While a 20g with only three fish in it look huge to you right now, it's really not that big a tank, and the average amount of fry per batch is around 20-30 fry. It can vary hugely though, there have been cases of many more, up to a hundred for a large female. Their first couple of batches tend to be smaller, but then they tend to have 20-40 every month/every eight weeks or so. Same deal for platies.

Platies can have 20-30 per month, every month, so with two females, say 60 fry per month just from the platies. Then the molly females having around 30 each every 6-8 weeks as well. Not all the fry will make it, the adults will sometimes pick off a few, but not all adults will eat fry, and there are still a lot that can make it.

See how the tank quickly becomes over-stocked and hard to manage?

If you want to breed, you really need to be prepared to have grow out tanks for fry, and have a plan for what to do with them once they're large enough. Some stores will take them, but not all will. My local store did, but I checked he would before I got my first guppies, and I stopped breeding them when that store closed down because trying to sell them privately means selling 1-3 at a time and all the hassle of time wasters and organising collections etc.
Also bear in mind that most stores won't take the fry until they're large enough to sell, so 3-4 months old for the platies, a bit longer for mollies. And while you're waiting for the first batches to get large enough for the store to take them, the adults have churned out another few batches.

It's your tank, fish and decision at the end of the day. Just want to make you aware, from my own experiences and the experiences of people who come here and bought a few livebearers and within six months they don't know what to do with their massively understocked tank, and overstocked tanks are prone to crashing once the amount of waste produced by all those fish causes a problem.

 

[Rollxr]

Not saying you can't - it's your choice! Just a heads up that the adults can get very large, given the change, and that the amount of fry can quicky become overwhelming. While a 20g with only three fish in it look huge to you right now, it's really not that big a tank, and the average amount of fry per batch is around 20-30 fry. It can vary hugely though, there have been cases of many more, up to a hundred for a large female. Their first couple of batches tend to be smaller, but then they tend to have 20-40 every month/every eight weeks or so. Same deal for platies.

Platies can have 20-30 per month, every month, so with two females, say 60 fry per month just from the platies. Then the molly females having around 30 each every 6-8 weeks as well. Not all the fry will make it, the adults will sometimes pick off a few, but not all adults will eat fry, and there are still a lot that can make it.

See how the tank quickly becomes over-stocked and hard to manage?

If you want to breed, you really need to be prepared to have grow out tanks for fry, and have a plan for what to do with them once they're large enough. Some stores will take them, but not all will. My local store did, but I checked he would before I got my first guppies, and I stopped breeding them when that store closed down because trying to sell them privately means selling 1-3 at a time and all the hassle of time wasters and organising collections etc.
Also bear in mind that most stores won't take the fry until they're large enough to sell, so 3-4 months old for the platies, a bit longer for mollies. And while you're waiting for the first batches to get large enough for the store to take them, the adults have churned out another few batches.

It's your tank, fish and decision at the end of the day. Just want to make you aware, from my own experiences and the experiences of people who come here and bought a few livebearers and within six months they don't know what to do with their massively understocked tank, and overstocked tanks are prone to crashing once the amount of waste produced by all those fish causes a problem.

So, I see what you’re saying. Also I’m not sure what you mean by ”Just a heads up that the adults can get very large, given the change.” Can the adult mollies get large for my 20 gallon tank? Is that what you‘re trying to say?