So far, in my desperate attempts to rid a tank of snails, my extensive (though limited) searching has led me thus far:
Pest snails are a big problem. I am talking about critters that are called:
Physa Fontinalis or Physa Acuta
(I think their common name is Bladder / Tadpole / Pouch Snails)
To I.D. them, do a Google image search based on those names.
Thier eggs are laid in a clutch and look light clear lumps of jelly, about 10mm in diameter. The clutch will contain between 15 to 20
little white dots that is each of the eggs.
The Problems
They eat everything (could be considered a good thing).
They can reproduce 'with themselves' - i.e. it takes ONLY ONE snail to infect a tank.
They multiply EXPONENTIALLY, i.e. 1, then 2, then 4, then 8 then 16, THEN 32, THEN 64!
Hence if left unchecked their numbers can explode to such a level that they can take over a tank and starve the tank (killing any fish).
They are horrible polluters: I once left about 10 snails in a bucket for about an hour and I could not believe the amount of poo.
They lay eggs (each clutch holding 15 to 20 snails with an 80% survival rate) that are hard to spot. You think you've got rid of the snails & then wham! 1 week later there are 20 more!
Worst of all they can get into your filter media!!! Making them nigh on impossible to eradicate.
ERADICATION METHODS
Chemical
’Had-A-Snail’ & ’eSHa Gastropex Snail Killer’ are just a couple of the many chemical solutions - usually using copper and sulphate ions . Apaprently 'Had-a-Snail works.
Problems: You'll pollute the tank with Copper [Cu]. You'll also kill any invertibrate, i.e. shrimp.
Some of these products simply DO NOT WORK. Some state that they 'knock them out'
And?
Hence due to copper pollution: I DO NOT SUGGEST USING A CHEMICAL METHOD
Fish
Add some snail eaters. This is the best method but you'll need a big tank.
Clown Loach is 'the' snail eater: However they grow to 12"+ and prefer to be kept in shoals of 6.
Second best alternative is a Yoyo Loach (Botia Lohachata or Lohachata Loaches): It is a smaller fish than the CLown & happier in smaller shoals and hence much better suited to smaller tanks. Unfortunately they are not very common.
Other snail eaters (I have yet to confirm effectiveness): Puffers, Hora’s (Skunk) Botias (unfortunately the most aggressive type of Loach), Opaline Gourami, Khuli Loach, Firemouth Cichlid.
Apparent egg eaters: Zebra Danios, Blue Ram Cichlid
Physical removal
Keep snail numbers under check by removing them by hand, using a veg such as cucumber or snail traps. These methods WILL NOT SOLVE THE PROBLEM. How can it? It does not remove eggs!
If there are any snails living inside your filter media 'sponges' (assume they ARE) then youu will not be able to get at them to remove.
DON'T crush any snails while they are in the tank - this will certainly kill the snail but may also release any eggs into the water.
Blitzing
Extreme & drastic: but unfortunately the only sure fire method to COMPLETELY eradicate ALL snails & their eggs. Also the only option left open to those who do not want to use chemicals in the tank or whose tank is too small for loaches.
Note: Cleaning could be easy if it were not for the fact that snails can and will get into the filter sponges. The filter sponges must therefore be discarded in order to rid the tank of the infestation. This is compounded by the fact that the filter media holds the essential ammonia busting bacteria that my have taken weeks to establish.
Transfer your fish to a second tank, water & all. Remove the heater and soak it for an hour in a very stong solution (i.e. 4 tsp per Litre of water) of Aluminium Sulphate or Aluminium Potassium Sulphate OR soak for 10 minutes in a 10ml / Gallon solution of Potassium Permanganate. Once done, thoughly rinse in tap water, then transfer to holding tank & switch on.
Remove substrate & bin it (leave plants behind). Remove any decorations and stones and BOIL them for at least an hour.
Snails and their eggs can be killed with a 2-day bath in ALUM (Aluminium Potassium Sulphate) using 1-2 tablespoons per 1 Gallon of water. Hence soak tank, all equipment and plants and in this solution with the pump running.
Remove the filter media, discard half of it and put the other half inside some tights (thus containing any snails therein). Knot.
To make DOUBLY sure the tank is clean of any snails, add 10ml / Gallon Potassium Permanganate - This will kill EVERYTHING (Snails, eggs, bacteria, algae). Add ½ tsp / Gallon water (i.e. 15ppm) for 10-20mins.
Once treated, rinse everything in water (with the pump running). Then add new filter media but only half filling the container. Now tranfer fish & water and heater back into original tank along with half the filter media that should still be wrapped in some tights. Wait a few weeks for the old filter media (inside the tights) to seed the new filter media. Then remove & discard the old filter media inside the tights replacing it with more new filter media.
Chemicals - where to get them
Get chemicals (in poweder form) from: www.gardendirect.co.uk
Andy
PS
My 'BLITZ' solution above is something I am CURRENTLY working on.
PERFORM AT YOUR OWN RISK