# high sunlight el natural crayfish tank



## ming shipwreck (Mar 24, 2011)

Hey y'all. I was really glad to find this forum.

I'd like to get some feedback on plans I have for an el natural crayfish tank. 

The tank is 20 gallons, long and low (30"x12"x12"), it's close to a south-facing window, it typically gets a ton of indirect sunlight and direct sunlight on parts of the tank for up to a few hours, especially in winter when the days are shorter (it gets almost no direct sunlight in the summer). I could move the tank, but I'd like to at least try keeping it where it is now.

The substrate is 1/4" peat moss, on the very bottom, then 1" potting soil, covered by 1/2" of sand from Lake Michigan (lots of shell fragments in the sand), and then 1/2 inch of mixed-size gravel from lake Michigan--mostly it is fairly fine, like coarser aquarium gravel.

My hope is that the crayfish won't be able to dig through the sand, because it's too fine for them to push or carry, and any tunnels they make in it will collapse. I have several large rocks (actually, mostly bricks and fragments of ceramic pots or roof tiles) that rest directly on the sand (beneath the level of the gravel), and a couple others that have only gravel and sand (no soil) under them, and are set up in such a way that the crayfish could tunnel under them without causing them to collapse (they are supported by larger rocks in some places).

plants: 
4 big strands of hornwort, 
4 strands of egeria najas, 
Eurasian water milfoil (to be taken from a pond near here, or my other tank--not added yet) 
1 water primrose
pretty small fragment of java fern from another tank
I also have planted some "betta bulbs": 
1 some sort of aponogeton, 
1 "water lily", 
2 onions. 

All the plants are anchored in the substrate, with large rocks inserted into the substrate around the "base" of the stem so the crayfish can't dig them up or dig under them. Of course, I can't stop the crayfish from clipping the stems with their pincers, I'm just hoping they won't do that (I've kept crayfish before, they never clipped stems).

animals I definitely want:
1-2 crayfish
3 mollies (from a friend who didn't have room in his tank--I may give them back to him if they crayfish bothers them too much)
pond snails 
Malaysian trumpet snails (to turn the gravel and help mulm fall through to the sand)

other animals I'm considering:
8-12 white clouds 
-or- 1 or 2 goldfish (need to research which ones don't get too big)
1 Siamese algae eater (not so much for algae control as because I have no place else to put him--they eat algae as juveniles but not as adults, or so I've heard)

So, what I'm wondering is, assuming the plants aren't dug up by the crayfish, will their roots draw enough nutrients out of the substrate to process the mulm that falls through the gravel? Most of the ones I have I think mainly draw nutrients from the water column, not the substrate, but if the roots extend far enough (milfoil roots seem to go pretty far) this might not be too big of an issue. Are there any plants you would recommend adding? I'm thinking something that will eventually become emergent, or else floating plants, maybe water hyacinth or salvinia, to overcome any lack of CO2 in the water. 

This tank will get a lot of light, so I'm assuming algae will be a problem, unless my plants are really good at competing with it. I don't mind scraping algae off the sides every so often, but I'm afraid of green hair obscuring all the nice gravel and rocks and things.

Thanks in advance for any suggestions.


----------



## Michael (Jul 20, 2010)

You've got the fast growing stem plants covered, so I'd suggest some deep-rooted plants. Vallisneria, crytocorynes, and sword plants come to mind. Sounds like an interesting project, keep us updated!


----------



## redchigh (Jul 10, 2010)

You don't mention which kind of crawfish... A pair of CPO would work wonderfully, but many other crawfish will eat the plants and fish...


----------



## ming shipwreck (Mar 24, 2011)

That was actually the point of this tank--I want the crays to rearrange the furniture a bit (it's fun to watch), so I was thinking to just get a pair from the bottom of the goldfish tank at the LFS, and make sure they're Procambarus acutus or P. allenii, not P. clarkii (which I think get larger and are more aggressive). I've kept crays before with guppies, they mostly ignored them, so I'm thinking the same will be the case with white clouds. Crays like to root around in the gravel but they don't do all that much damage to the plants directly, and worst case scenario the egeria and fanwort can just float and stay out of their reach. Though, I was thinking to just load up the aquarium with those things, so the crays have extra food and their growth compensates for any damage done. If the crays won't let any of the plants stay rooted, I figure I'll just screen off a couple small parts of the tank and put Vallisneria in there and if the crays chew off runners that poke through the screen, no big deal.


----------



## ming shipwreck (Mar 24, 2011)

Just a quick update:
I've added a lot of anacharis, 2 cryptocoryne plants, a tiny bit of water milfoil, 3 strands of bacopa monnieri, and 5 stems of hygrophila difformbis, in addition to the egeria najas, water primrose, and cabomba that was in there already. Except for the hygrophila which I just added, all these plants enjoyed a long weekend alone with unfed crayfish, with the following results:

anacharis: A good bit of the anacharis has been eaten, however it grows very fast in this tank, so it is possible I could fit enough of it in the tank for it to grow back faster than they eat it.
crypt plants: They are like crayfish spinach. About 1/2 the leaves gone already. I doubt they will survive in this tank (the pot came with 3 plants, the 3rd one I planted in another tank, so this won't be a total loss).
water primrose: got some leaves and maybe a stem munched on, but is mostly intact, however a lot of the leaves had fallen off when I planted it.
water milfoil: top gnawed off--if this were planted thickly, it might do okay
cabomba: they don't seem to have disturbed the cabomba very much at all.
bacopa monnieri: also mostly undisturbed, though I do see a couple places where they nibbled on a leaf.

I've been looking for a species of echinodorus that won't grow too big for my tank, but none of the stores around here are carrying anything like that. I added more cabomba and the hygrophila difformis, I figured if the crayfish are going to nibble on the plants that much I might as well plant things in there that can grow like weeds. 

I will try to get a bunch more water milfoil (it grows around here), and (perhaps) whatever type of echinodorus or vallisneria I can find that won't grow way too big for my tank (so no more than 8" high).

I'm hoping that keeping the crays well fed and also throwing a lot of snails into the tank will keep the crayfish from eating the plants faster than they can regenerate.


----------

