We have had fish for the last six months. In the last two months the tank seems to weed up with a very fine web like weed and we have more snails than stones. The stones are also greening over and our guppy can no longer cope with the cleaning job.

Any ideas how to control all this?

how often do you change water/ clean the substrate? what size tank, how many fish, what are your water parameters, how long are the lights on for, is the tank near a window, how much are you feeding.

all of these can have an effect.

Snails probably arrived with any plants you may have added to your tank. They are not necessarily pests, though: while some species are voracious towards plants, other feed almost exclusively on decaying matter (such as dead leaves and food your fish didn't eat), as such they can help keep your tank cleaner.

If they really bother you, though, bear in mind some fish or carnivorous snails (such as Anetome helena) happily feed on them and can rid you of them.

Said so, I second rob - if you can provide more info about you tank (including whether it is coldwater or tropical, what kind of fish and plants you keep, etc) it'll be easier to give you specific advice.

90 ltr tank with 12 little fish and the guppy.

Water is kept at 24C and one third is changed every three weeks. Lights are on for 12 hrs. The tank is located away from the window although the room has good natural light.

Fish are fed one pinch each morning.

Thanks for responding.

I attach a photo to give you a sense of the tank etc.

ok so no over stocking, make sure you do a very good clean of the ground when doing a water change. knock the lights down a bit and see what happens. i would increase the water changes also as you have a small filter

Easiest way is to get some quick growing plants - the algae is because of excess nutrients so quick growing plants will compete for this. go for water wisteria - it grows quick and looks ok and isn not hard to grow.

to remove snails you have 2 options, by hand or by natural means - look for assasin snails, they look quite nice and will love to help you with the snails!!!