General questions?

[CaptainMako]

Hey everyone, I had some questions about what I can add to my first tank in the future once my fish are fully grown.
I have a thirty gallon brackish tank with six dalmatian mollies, they are still young and maybe about an inch and a half long average. I do not know the sexes.
There are no plants and the tank's health is just fine, the brackish water varys a little if I am forgetful of it, this ties into my questions.

1. Does salt stay in the water until it is all gradually taken out with PWC's? Do I need to add more each PWC?

2. The community has already given me some suggestions as to what fish I can add, but I had some thoughts on what they didn't include. Would I be able to add a bottom-feeder or a snail with this kind of tank? Some friends of mine have a pretty big black bottom feeder, it may even be a catfish, I would kill to have the exact same but keeping it pent up in a 30 gallon tank seems almost too small to me.

3. Generally, how long will it take the mollies to reach full adult size?

4. I see plenty of folks here feeding their fish vegetables like peas or lettuce, and apparently the Tetramin flakes I feed them are not very healthy. What is a brand I can switch to, and if I start incorporating vegetables, what should I start with?

Sorry for pelting you guys, I just think of these things randomly and realize I need the answer. I will upload some pictures of the tank by tomorrow hopefully. Take a gamble at what that black bottom feeder might be if you can, I would love to have one.

Thanks a bunch community!
Shaun

 

[Shadowraven]

I'll try taking these on. Let's see...

1. Does salt stay in the water until it is all gradually taken out with PWC's? Do I need to add more each PWC?

The short answer is, yes. Salt does not evaporate with water. The only time that this will change is when you do a pwc. You're diluting the concentration of dissolved salts by adding new water.

2. Would I be able to add a bottom-feeder or a snail with this kind of tank?

Most snails generally can't live in saltwater. It will kill them. Malayan livebearing snails and Nerites are an exception. They both can do quite well in a brackish water tank. Whelks can usually tolerate saltwater as well.

There are catfish that can be used in brackish systems, but most of them get too large for your type of setup. Never put a Corydoras in any saltwater.

Your best bet here would be crabs. Crabs are excellent scavengers and fun to watch to boot! Many of them are sold for freshwater, but they don't do well there. All freshwater crabs that I know of are actually better suited to brackish water conditions. Since they are air-breathers you will need to provide with a shelf or space for them to crawl out of the water occasionally.

There are shrimp that are good choices too. You can follow this link to learn more.

3. Generally, how long will it take the mollies to reach full adult size?

That is temperature dependent, but is usually a few weeks to a couple of months. Mollies have a lifespan ranging from 3-5 years.

4. I see plenty of folks here feeding their fish vegetables like peas or lettuce, and apparently the Tetramin flakes I feed them are not very healthy. What is a brand I can switch to, and if I start incorporating vegetables, what should I start with?

Prepared food isn't all bad. Just be sure to buy the higher quality foods. They will reduce your ammonia load and keep your fish healthier. Hagen makes some good prepared foods for your fish.

Whatever you feed them, you'll need to regularly supplement it with other foods like algae wafers, cucumber, blanched lettuce and cooked spinach. They also love frozen foods like brine shrimp and the like. Too much prepared food can give fish constipation, which in fish can be fatal. The occasional treats 2-3+ times a week, like I mentioned above, should keep them in top shape.

 

[CaptainMako]

Thanks a bunch. It's nice knowing I can come here and get reliable information. Appears I'm not quite done yet though, additions to the same questions.

1. So adding just a small amount of salt each PWC should, in theory, keep the water at a decent salinity?

2. I like the idea of getting a crab, but I'm lacking knowledge on them. I understand the shelf, but can they easily reach the shelf after scavenging around on the bottom of the tank? Basically, can they navigate well by themselves if the only changes I make to the tank for them are adding the shelf?

 

[DragonFish71]

Get a hydrometer and keep an eye on your SG. You'll know when you need to add salt. Set yourself a a specific SG, I keep ours at 1.015 for most of the month then let it drop to about 1.008. I try to mimic the tidal fluxes that happen in nature (as best I can)

Ghost shrimp, nerites, and MTS go great in BW. I had regular ramshorns as well, the shrimp loved them. They would stand on them and rip out chucks. It was gruesome and cool at the same time.

By the way, SG is specific gravity.

 

[Shadowraven]

Yeah, it's funny that something that looks so delicate can be so vicious isn't it?

DragonFish gave you a good answer about your salinity, I'll tackle the crab.

Crabs won't be able to reach anything on the surface without something to climb on and reach it. Unlike shrimp most crabs can't really swim. They will need a background, plants or something else to use as a ladder to reach the surface. If they don't have an access route, they will eventually die.

 

[CaptainMako]

I think my thermometer has a hydrometer on it as well, but I never understood how to use it. It didn't have a bar of anykind, just a strip of paper with a green blot on it, I've never seen it move.

And I've seen some people talking about ramshorns on here, I almost always see them being dubbed fodder.

Can they climb anything really? As long as it's firm and static?

 

[Shadowraven]

Not a hygrometer, which measures relative humidity. You need a hydrometer, which will help you measure the salt concentration in the water. It measures the relative density of liquids.

Yes, crabs can climb anything. They are quite accomplished escape artists as well. So make sure that there are no gaps in the hood of your aquarium. Otherwise you will find them outside the tank crawling across the floor!

 

[CaptainMako]

Sorry, was typing this as you replied. Thank you for clarifying, I've never heard of a hygrometer.

Oh, and another thing. When I first got the mollies and I was super concerned about their health, I think I may have misdiagnosed them with freshwater velvet. Luckily I didn't have the chemicals to treat them or I probably would have killed them.
They have had these little rust colored spots, each of them, since they were born. They were fry from a black and white molly, but I remembered that the tank both of those mollies were in also had some orange-colored fish, platys I think.
Is it possible they have orange pigment from the platy some how? I figure if it were a disease they would be long gone by now.

 

[Shadowraven]

See my post above, I had a brain fart while I was typing. I fixed the information that was mistyped.

 

[Shadowraven]

How long have you had the mollies and how are they behaving?

As for the other, I seem to remember hearing of molly/platy crossbreeds, but I'm not sure. I'll have to research that further.

 

[CaptainMako]

All right. When I upload the pictures of my tank I will include one of the thermometer/hydrometer and see if you guys can direct me a little bit.

I love the crab idea now. I do have some plastic plants in there and a few lava rocks, but I'm not so sure about them being able to climb the plants, which reach up to the water's surface. Of course, I don't know how much an average crab weighs.

I've had the mollies for maybe 3 months at the very most. They are probably 4 or 5 months old, that part I am unsure of. They behave normally, or at least as normal as I would expect being as how they are my first fish. They swim in pairs most of the time and always come up to the surface for food when I approach the tank.
I have heard of mollies and platys being able to cross breed, but I just don't understand how that could be if both of the parents are mollies with different colors.

 

[Shadowraven]

Then you should be OK. If it was velvet, it would have spread, and they would be long dead by now. As long as they have a good appetite and aren't exhibiting strange behaviors, there should be no problem.

 

[Shadowraven]

The freshwater crabs that you can get at the store are small. No larger when grown than a half-dollar coin. They are pretty light. They sometimes have trouble in artificial plants due the plant's stiffness and slick surface. Driftwood also makes a very nice ladder/platform for them if it projects from the water, or reaches your platform.

 

[CaptainMako]

That's what I was thinking. The spots have stayed in a single spot even as the fish grow. I wish my camera was a higher quality so they would actually show up when I got pictures of them.
The last question I can think of is my tank temperature. Everywhere I look I see the ideal temperature for mollies is upwards of 72 degrees or so. For the most part I can keep it here with the setting my heater is on, but my room is the oddball. Summer it is the hottest room and winter the coldest. There's a fan on low power in my room every night, and because the heater has a light on whenever it is on, I can see the mollies crowding around it at night. I worry they don't rest or they get shock of some kind.
Anyone have ideas, opinions? Maybe they are perfectly fine, they sometimes just hang around it for no reason even if the temperature is fine.

And just saw the crab post. I pictured them as full size crabs, lol. Happy they are smaller. I don't think my local Petco (next to my only option) carries any, but I can check. A saltwater-exclusive LFS I've found should have some? I doubt they can deal with brackish water though, dumb question.

 

[CaptainMako]

Shameless bump

 

[Shadowraven]

I was answering your posts from another location. I just got home to answer your questions again.

I don't know saltwater that well, but I don't think that you would find these types of crabs in a saltwater shop. Not unless they carried BW or FW animals.

Mollies prefer temperatures from 70-80F. If you have hot spots in your tank while the rest of it is cold, then place your heater in an aeration column or by the filter outflow into the tank. That should help even the temperature out through the tank.