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lsoucy

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I have heard many, many different things when doing research on Molly fish. I am interested in having mollies in my 20H gallon tank. How many can I fit? I just want as many opinions as I can get. Any info will be greatly appreciated! If it makes a difference, my tank is 24 inches left to right, 12 inches front to back, and 16 inches deep.
 
Hello! Mollies each get 4-6 inches. I would only suggest 1 or 2. No more. Is your tank cycled?
 
Agree, and just to explain why...this is not a small fish. Males attain 3 inches, females close to five inches with some six inches. And they are incredibly sensitive to water conditions, which is why more volume is better.
 
Hello! Mollies each get 4-6 inches. I would only suggest 1 or 2. No more. Is your tank cycled?
I am slowly gathering supplies for my tank, so it is not cycled yet. I know I can't truly decide on stock for the tank until I know the parameters of the tank. I began thinking about stocking my tank loosely based on the parameters of my betta tank :)
 
Agree, and just to explain why...this is not a small fish. Males attain 3 inches, females close to five inches with some six inches. And they are incredibly sensitive to water conditions, which is why more volume is better.
Wow! Good thing I haven't set my tank up yet! What fish would you recommend for my tank?
 
Before we can recommend fish, we need to know your source water parameters. This primarily refers to the GH (general or total hardness) and pH of your tap water. You should be able to get these values from the water authority, check their website. The GH is not likely to alter much in the aquarium, depending what it is to begin with in the source water, and the pH is tied to this. The pH may lower as the tank water acidifies (normal), or it may not, depending upon the GH and the KH (Alkalinity) and some other factors, but knowing the GH gives us a relatively good idea of what the pH is most likely to do.
 
Before we can recommend fish, we need to know your source water parameters. This primarily refers to the GH (general or total hardness) and pH of your tap water. You should be able to get these values from the water authority, check their website. The GH is not likely to alter much in the aquarium, depending what it is to begin with in the source water, and the pH is tied to this. The pH may lower as the tank water acidifies (normal), or it may not, depending upon the GH and the KH (Alkalinity) and some other factors, but knowing the GH gives us a relatively good idea of what the pH is most likely to do.
The water report for my city was posted last year (or at least the one they had on the website was). Hopefully these numbers make sense! These are copied and pasted straight out of the report;
pH (Standard Units) 7.55
Hardness, Total as CaCO3 (mg/L) 38.7
Alkalinity, Total (mg/L as CaCO3 )16
 
The CACO3 at 38 is roughly 2 dGH, just for comparison. This is very soft water. The Alkalinity at roughly 1 dKH will allow the pH to lower. So you want to be considering soft water fish species.

Mollies need much harder water so even with a larger tank they would have considerable difficulty and not last long.

Fortunately with very soft water you have many options. Most of the small species from South America (tetras, pencil;fish, hatchetfish, cories) and SE Asia (dwarf rasboras as an example) are what you want to look into.
 
The CACO3 at 38 is roughly 2 dGH, just for comparison. This is very soft water. The Alkalinity at roughly 1 dKH will allow the pH to lower. So you want to be considering soft water fish species.

Mollies need much harder water so even with a larger tank they would have considerable difficulty and not last long.

Fortunately with very soft water you have many options. Most of the small species from South America (tetras, pencil;fish, hatchetfish, cories) and SE Asia (dwarf rasboras as an example) are what you want to look into.
Thank you so so much for your help! Hopefully I can find a fish to fall in love with! I was thinking maybe a community tank could be fun...any quick suggestions I can look into? Sorry for harping you, just excited to find someone who can help! :)
 
You're welcome. I tend not to recommend specific fish as aquarists should have what they like, but I am always willing to pint out problems to avoid them if you find fish you might like. Just ensure you research the fish (post here on TFF for comments) before acquiring them, and you should be OK.

There are many options, but you need to keep the relatively small tank in mind. Most of these fish are shoaling species, meaning they must have a group of their own species, and while minimums like six are often suggested, it will always be better for the fish to have a few more, so don't just think "minimum" numbers.

Another thing to keep in mind is that the smaller the fish size, the more of them you want, but also it means you can have more variety with more than one or two species. If you were to decide on slightly larger fish, then your options would be less obviously.

Lighting is critical here too, as these fish are forest fish that do not appreciate bright overhead lighting. This is where floating plants can help. Lower plants are trickier, but nothing can be much easier than floating plants, and they will shade the aquarium so the fish will be brighter and settled. Lots of wood including branches will create an authentic aquascape. Sand is a good substrate, as some fish need it, but it too is authentic and will help to expand the visible space better than gravel. Now is the time to change the substrate if you have gravel and want to change it. A bag of play sand is very inexpensive.
 
You're welcome. I tend not to recommend specific fish as aquarists should have what they like, but I am always willing to pint out problems to avoid them if you find fish you might like. Just ensure you research the fish (post here on TFF for comments) before acquiring them, and you should be OK.

There are many options, but you need to keep the relatively small tank in mind. Most of these fish are shoaling species, meaning they must have a group of their own species, and while minimums like six are often suggested, it will always be better for the fish to have a few more, so don't just think "minimum" numbers.

Another thing to keep in mind is that the smaller the fish size, the more of them you want, but also it means you can have more variety with more than one or two species. If you were to decide on slightly larger fish, then your options would be less obviously.

Lighting is critical here too, as these fish are forest fish that do not appreciate bright overhead lighting. This is where floating plants can help. Lower plants are trickier, but nothing can be much easier than floating plants, and they will shade the aquarium so the fish will be brighter and settled. Lots of wood including branches will create an authentic aquascape. Sand is a good substrate, as some fish need it, but it too is authentic and will help to expand the visible space better than gravel. Now is the time to change the substrate if you have gravel and want to change it. A bag of play sand is very inexpensive.
Thank you for your help! I will not hesitate to create a new post once I have my tank fully set up!
 

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