Help with low maintenance outdoor setup for crayfish and mollies

[Gp!]

This technically doesn't make me think pond - but I see a lot of threads in here for stock tanks.


I've grown mollies outside in salt water with basically no maintenance just using rocks and water movement for a couple of years now. Water change once or twice a year. Algae grows and seems to keep the water clear enough for them to be happy. They were just supposed to be feeders but then I decided that I liked them =P. Now I'm up to hundreds in only around 200 gallons of water or less when you factor for the rocks.


So with that being said, I am looking for advice to set up a better (but still low/no maintenance) system for growing crayfish and mollies outdoors with freshwater.


I was thinking of using Rubbermaid stock tanks. But welcome any better suggestions as the current set up is a bit of an eye sore. Any recommendations as to how I can make it look nice would be appreciated. But I don't think I'm going to be digging a real pond.


Currently I just have the setup full of large rocks with a bare bottom. I'm going to use lava rocks on the bottom this go around for the crayfish. I've never kept crayfish before but they seem fairly straightforward.


With all that in mind, what type of filtration would you recommend? Should I use floating plants? Should I just stick with the concept that is working and just automate water changes?

 

[Muckfish]

The lava rocks would be good for the baby crayfish to avoid being eaten by larger crayfish. Small pvc pipes work as good hides as well for the crayfish. You may want to try those cloning crayfish

I think a large sponge filter and live plants would be adequate and beneficial for the stock tanks. The sponge filter would help cut down on turbidity from waste particles and help oxygenate the water at night when plants may be consuming oxygen.

 

[C. Breeze]

I keep a few species of cichlids, gambusias, and sailfin mollies outdoors in stock tanks all year. The gambusia and mollies were local Collections to me here in coastal ga.
No sponges. No bubbles. No electricity. No turbidity. All of them are clear except the 2 that get a lot of pine needles that drop. Those are tannic but you can still see to the bottom. I thin the plants at this point shown in the picture. . I keep about 1/4 to 1/3 of the surface clear for viewing. I top off or rain does every couple weeks. I maintain 10 outdoor vats from 110-1000 gallons.

 

[jjohnwm]

I agree completely with C. Breeze ; the simpler, the better. The first time I tried to "improve" one of my outdoor stock tanks by adding a sponge filter, I figured that it had to be a big step up, right? Wrong! The water circulation produced by even that small diaphragm air pump turned the water over enough in a 150-gallon tank that there was almost no temperature stratification at all. Even in my northerly location, over 50 degrees north latitude, there are enough warm summer days with plenty of sunlight to raise the water temperature up into the 90-95F range. In still water...the word "stagnant" has such negative connotations that I am avoiding it, but that's what we are talking about...only the top inch or two gets that hot, leaving the bottom of the stock tank comfortable for the fish. But when the water is circulated, all of it gets too warm. In this oddball case, additional aeration results in lower oxygen levels, as the warmer water holds much less dissolved oxygen as it heats up.

I think that part of the problem is rooted in the black colour of most stock tanks. Sunlight beating on that exposed black surface heats it up quickly, but even the single blue tank I have is prone to overheating during summer, although to a slightly lesser extent. I shudder to think how much worse the problem would be in more southerly climes...i.e. all of the U.S. with the exception of Alaska. A sunshade arrangement helps out a lot, but at the cost of slower plant growth.

As far as aesthetics are concerned, a friend in Ontario had a round stock tank on his patio which he encased in a ring of rounded cement bricks that are sold for the construction of fire pits. The only part of the tank still visible was the top lip, which could probably be easily hidden by some type of wooden lip or facade. If I ever decide to locate one of my stock tanks on the patio, I will need to try something like that; otherwise, the shrill complaints from my wife will detract from my enjoyment of the fish.

One last comment: the species of crayfish I have kept have all been extremely destructive to aquatic plants. I don't think you will be too pleased with the appearance of a stock tank with no plants, especially when the water turns pea green with algae.