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Population Bomb

1675 Views 5 Replies 4 Participants Last post by  Dustymac
Hi all,
NPT #3 is a 55 gallon tank that gets about an hour of direct sunlight every day. It's heavily planted with crypts, vals, swords and ludwigia repens. The plants are doing great and there is little algae. For fish, there are a couple large Angels and 6 mature guppies. There is no water filtration - just a submerged pump for circulation.

My problem is about 200 Apple snails and maybe 300 Pond snails, and I'm wondering if this is just too much. You can tell the snails have stopped growing with the Apple snails averaging about 3/8"-1/2" diameter. The four original Apple snails died, evidently from starvation - only the vals look like they've been munched on.

I've also noticed the water getting very faintly cloudy compared to the crystal clear water in the other three NPTs. And just this past month, one of the guppies gave birth and it looks like 20 or so have escaped the Angels and will be allowed to mature unmolested.

So far the fish haven't shown any signs of oxygen deprivation but I'm worried about the cloudiness and whether I need to remove some of the animal life, specifically some of the Apple snails. Any thoughts?

Thanks in Advance!
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Apple snails get big! I have had bad luck with those as I have soft water. I am by no means an expert, but that many snails will use up a lot of calcium, especially the apples. Whenever I notice a lot of small snails and not to many full-grown ones, I remove a bunch of them and add some crushed oyster shells, especially if snail shells start looking a little thin.

Your plant selection sounds solid! How heavy is your plant load? Is there tons of plants, or only a few? The cloudy water might be a bacteria bloom, which means to many snails. Are you sure your pump is not just kicking up detritus?

Hopefully people with more experience will chime in. I have always wondered how snails factor in to the fish load, you always hear 1" per gallon of fish, but how many snails per gallon?
With that many snails it would probably be a good idea to thin the population as apple snails will get big and add quite a bit to the bio-load of the tank. I think the number of snails is contributing to the cloudy water. Apple snails are popular so you can probably sell them if you'd like.
Thanks for the response and the reminder to check the hardness of the water. Our NPTs have been so stable and carefree, I forget that our water is very soft, too. The two tanks with the largest snail populations were reading 4 on the GH scale. I gave each half a dose so we'll see.

I also have a halfway decent microscope and put some of the cloudy tank water under the lens. You can plainly see the suspended particles and zooming down reveals what looks like bits and pieces of decomposing plant tissue. This made me take a hard look at the plants and along with the vals, some of the newer sword leaves are looking a bit ragged.

Whether or not this has anything to do with the snail boom, it's hard to say. Did the snails take the calcium out of the water, causing the plant decomposition and cloudy water? I can't say, but without doubt this is the most fascinating hobby!!! :)

Anyone want any Apple snails???
assassin snails. they will mercilously eat any other snails in the tank

I'm not sure of the cause, but the water is clear now. Here are the steps performed:

#1) Transferred about 100 (half) of the Apple snails to the other NPTs.

#2) Performed two 15% water changes.

#3) Installed a HOT canister filter with only filter floss to remove floating debris.

#4) Installed a UV sterilizer/filter.

#5) Installed an aerator to improve lower level water circulation.

What exactly cleared the water is hard to say, perhaps all the steps contributed. I definitely think letting the water hardness slip caused the decomposition of the vals and the water cloudiness. (Page 117 of the book...Doh!!!) After I get the water hardness back up to normal, I plan on removing the two filters. Don't know about the aerator. Perhaps I'll replace that with a lower level water pump.

About the UV filter, are there any guidelines for using them in a NPT? Do they affect the plants in any way? Do I need to remove it or is it best to leave running?

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