Questions about Mollies

[St. Louis Cardinal Tetras]

Hi, I am setting up a community tank in a 29 gallon. The fish I want to have in it are cardinal tetras, guppies, Cory cats, a pleco, and gold dust mollies. I have done extensive research on each species and have all their water parameters written down. My question is how important is water hardness to mollies? I have read through so many articles and forums and they all go back and forth. When I first started I got a lot of my info from Prime Time Aquatics and KGTropicals on YouTube. They have taught me so much and I respect their opinions. But after watching both channel’s videos on best community fish and stocking options for 29 gallon tanks, they both recommend mollies. From what I can gather on the internet is their is a lot of confusion around the Molly species from people saying they can only survive in brackish water, and some say they do completely fine in fresh water. Similarly people say they can only survive in hard water environments, but then other people say their fine in soft water. My water out of my tap is soft. Now this is perfect for my cardinal tetras(possibly my all time favorite fish) but will the mollies be ok? Essentially, do you guys have mollies with tetras or in soft water? If so, are they healthy? Did you use an extensive acclimation process? I was thinking about going with platties instead but not a very good variety in my area. 

[KBOzzie59]

Live bearers like harder water (your guppies and mollies).  And...  depending on your actual stocking you may get a molly/guppy hybrid here and there.  Platties like hard water as well.

 

edit: my clicker got ahead of my brain!

I have male guppies and male platties in a community tank with candycane, rummy nose, black phantom, and silver tip tetras.  Also 2 super red bristlenose & 2 baby plecos, a handfull of kuhli loaches, a dwarf frog.  I think that's all.  IMHO livebearer water hardness really only comes into play when breeding.  I will test hardness when I get home but I'm not supplementing and my tap water is very soft.

 

edit #2: My breeding tanks do get supplemented as needed.

Edited April 14, 2021 by KBOzzie59

[St. Louis Cardinal Tetras]

Thank you. Yes I know livebearers like hard water but from what I’ve read it seems like guppies and platties are more tolerant to soft water than mollies. But then I’ve seen a lot of people that say that their mollies do fine in soft water. I also read that a lot of the problems that mollies have are attributed to them being in soft water but are caused by other things like how they are cared for, bred, or just poor care from LFS. I might just scrap the idea of mollies and order some raspboras. There’s not a very good variety of those around my area but there are plenty of mollies which originally led me to want them. And my girlfriend loves the gold dust mollies because she says and I quote “it’s like having my favorite outfit in a fish” lmao. Her favorite outfit is a black romper that has gold shimmers on the top. Getting her as fired up for this new hobby as I am has proven to be a task so I was hoping the mollies would interest her more. 

[St. Louis Cardinal Tetras]

12 minutes ago, KBOzzie59 said:

Live bearers like harder water (your guppies and mollies).  And...  depending on your actual stocking you may get a molly/guppy hybrid here and there.  Platties like hard water as well.

 

edit: my clicker got ahead of my brain!

I have male guppies and male platties in a community tank with candycane, rummy nose, black phantom, and silver tip tetras.  Also 2 super red bristlenose & 2 baby plecos, a handfull of kuhli loaches, a dwarf frog.  I think that's all.  IMHO livebearer water hardness really only comes into play when breeding.  I will test hardness when I get home but I'm not supplementing and my tap water is very soft.

Yes that is exactly what I was thinking about it only being important if you are breeding them. I was planning on getting all males anyway just because I do not want a bunch of fry. And that sounds like an amazing tank! I don’t know what it is about platties but i have yet to see one in person that strikes my eye. But like I said not much of a variety around here.

Edited April 14, 2021 by St. Louis Cardinal Tetras

[anewbie]

I believe it is more important for the cardinals to be in softish water than the live bearers to be in hardwater. I can't really make any definitive comment on water hardness and longevity but certainly in my experience with live breeders they will readily breed and live many years without special water treatment but the cardinals are a bit more demanding. While the cardinals can adapt to hard water (tank bred are better at this than wild caught) there are limits.

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Also we throw around terms like hard water and soft water without qualification. I keep my fishes in water that is gh 7 kh 3 which is not super soft but also not exactly hard. Anyway my swordtails and guppies have no problem producing more frys than i want or for that matter any of the other fishes in the tank want and my oldest swordtail is now 4 years old - though just looking at him you can tell he is a bit long in the tooth. Sadly i cycle through the femals giving the to the lfs as my fish population grows so i've not kept a female more than 18 months or 2 years. The guppies are not as long lived lasting only a couple of years... 

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Anyway unless your tap is extreme in either direction i would try to stick to tap as treating the water risk shocking the fish when you change the water (new water not same hardness as old water). There are exceptions to his - as african cichlid require hardness water 10+kh and many more sensitive south american   cichlid require very soft water (0-1 kh - 50 tds).

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Guppies and mollies do ok in brackish water but i cannot state (again) the long term impact relative to fresh water.

Edited April 14, 2021 by anewbie

[St. Louis Cardinal Tetras]

Thank you two so much! After a week and 4 google pages, you two have given me far more information in an hour!! I love this forum and I love how helpful everybody is in this hobby. I can’t wait to get my tank stocked so I can post pictures. I’ve had my tank for about a month now but I want to make sure I know and understand everything before I just go throwing fish in there. 

[quikv6]

When I was starting up my tank, I chose mollies to be my first fish of choice. I have soft water (roughly 40-50 ppm GH), but made the mistake of not knowing that at the time. Rookie mistake.

Did they survive....yes. Were they happy....I don't think so. I didn't really fully recognize the difference until I doctored my water a bit, with Wondershell and Replenish/Equilibrium. Once I did that, they went from a bit of the shimmies and overall lethargic behavior, to zipping around the tank, mating, and overall just being way more active and playful.

Right now I boost my GH up to around 200ppm, and the 75 gallon tank will of Mollies and Platies seem to really appreciate that.

Just my .02. I really wanted the fish to thrive, and give them as close to a preferable environment as I could. In return, they really seemed to thrive, which is rewarding, and makes for more enjoyment.

 

Edited April 14, 2021 by quikv6

[quikv6]

If I may add....I couldn't be happier with choosing mollies. It's a great choice, and they have A TON of personality. What I have noticed it that there are more personal characteristics to them, as opposed to the platies, which seem to have more broad species characteristics.

Mollies are definitely fun, and quite goofy at times....which is even more fun. 🙂

 

 

[St. Louis Cardinal Tetras]

9 minutes ago, quikv6 said:

When I was starting up my tank, I chose mollies to be my first fish of choice. I have soft water (roughly 40-50 ppm GH), but made the mistake of not knowing that at the time. Rookie mistake.

Did they survive....yes. Were they happy....I don't think so. I didn't really fully recognize the difference until I doctored my water a bit, with Wondershell and Replenish/Equilibrium. Once I did that, they went from a bit of the shimmies and overall lethargic behavior, to zipping around the tank, mating, and overall just being way more active and playful.

Right now I boost my GH up to around 200ppm, and the 75 gallon tank will of Mollies and Platies seem to really appreciate that.

Just my .02. I really wanted the fish to thrive, and give them as close to a preferable environment as I could. In return, they really seemed to thrive, which is rewarding, and makes for more enjoyment.

 

I’m the same way as you. I want my fish to be healthy and happy. It can just be so confusing sometimes. When I watch the channels I trust on YouTube, they’ll be talking about a random fish and say usually this fish needs this but we have them in this tank without and they seem to do fine. If I get them I will keep a close eye on them and if I see that they aren’t as lively as they should be I’ll return them to my LFS.

[quikv6]

I think that is a solid plan. For me, I knew I wanted the mollies, so I made the choice to alter the water pretty shortly after getting them. I should add....out of the tap, I had lower PH/KH as well, so their initial lethargy could've been a combination of that too. (I altered that w/ a bit of baking soda and crushed coral.) It was only then that I really saw the thriving behavior that I was missing.

Best of luck...sounds like you'll have a great tank. Keep us posted!

Edited April 14, 2021 by quikv6

[St. Louis Cardinal Tetras]

I’m fighting the urge to just get a 20 long to have a dedicated live bearer tank. I do love all the varieties of mollies. I just don’t really have the room and I’m not sure if my girlfriend has the patience  lol. I have like 6 months in my lease at my current house and I’m already looking at houses with finished basements so I can have a fish room. This hobby is so addicting. Isn’t that the first symptom of multi tank syndrome? Not even having fish in your first tank yet but thinking of setting up another. 🤣🤣

Edited April 14, 2021 by St. Louis Cardinal Tetras

[quikv6]

A 20 long is a great tank. I understand the urge. I started with a 20 high, with 3 mollies and shortly thereafter added 3 platies. After the first batch of fry...I immediately knew I needed a bigger tank.

Then came the 40 long. (Also a great size, that isn't often spoken about) Then came a few more batches of fry, and the 75 gallon tank they are all currently in. Enter the PetSmart Black Friday sale on a 125 combo. It's currently sitting, patiently waiting to be swapped out with the 75. I am dreading the swap, and the work involved, but I know it will be worth it when it's done.

Short story: I hear ya!

 

[St. Louis Cardinal Tetras]

I was originally going to get a 20 long but they were out of stock at my pet smart. I wanted to get a starter kit which I regret now because I know I’ll have to replace the filter and heater probably within the next 6 months. But I got a sponge filter to help out the HOB it came with so when it does go out I’m not screwed. And I’m sure that switch to the 125 will be a lot of work but it will be SO rewarding! I can’t wait to see pictures!

[1moretank]

Many times I have seen the recommendation to buy the biggest tank you can afford/fit when you start.  Such good advice.  I have kept mollies in very soft water, soft water with crushed coral, and in hard water (I moved).  If I had to go back to soft water, I would add crushed coral because I think it makes the water quality better for all fish, but mollies and guppies will definitely appreciate it and it won't adversely affect the tetras.  In my experience, some of the bigger mollies can be a bit of a bully to smaller fish, others never bother smaller fish at all.

[anewbie]

While I love 20 longs for various fishes a 29 might be a better fit for your dedicated live bearer tank. The 29 is a 20 long that is taller. I use mine with guppies and swordtails. One thing i've learned is swordtail frys love to stay in the substrate while guppy frys love to stay at the very top (can't comment on molly frys). Also if you have a petco near you they frequently run these $1 per gallon sales so a 29 is $29 and a 20 long is $20 - they are't kits just bare tanks but still pretty good price for the glass.