I have a tub outside my balcony which I grow my water lilies. I put an UGF folowed by pebbles followed by water lily clay that you can find in the botanic shops. Is it the correct way to apply lily clay? I wonder if the clay itself is like soil (it cannot be exposed or it will leach chemicals?)

The reason I ask is because I tried putting guppies, mollies and swordtails into the pot and the only fish that can survive are the guppies. My swordtails go haywire in their ability to swim after awhile then they die. My baby mollies magically dissapear (bird ate them?)

I have cycled the pot for at least 3 weeks before introducing the fish. I tested the water for ammonia and the reading is very low (0.1?????). Makes me wonder if the clay is the culprit for the fish's death. In which case, must I cover the clay with a layer of holland sand?

Have you ever wondered if it was the heat? your balcony gets pretty hot if i'm not mistaken though i wouldn't discount other causes.

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Clay can be used as a medium as long as it's settled down.. but fish is sure to pick at it and churn up the water.. I would buy a fresh pack of water lily clay if I were you. If you recycle yours.. it might have some fertilizer or some other stuff packed into the clay leaching into the water and killing your fish. I've no problems with fish and clay.. they seem extremely healthy even when put in a tank that you can't see nuts in. It's non toxic but small particles might clog up the gills if it's been murky for too long. Ammonia even in small amounts is toxic. It should read 0.

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Learn how to cycle and you'll never forget how.

Hmm... will put a thermometer to confirm that. But the funny thing is, my 2ft tank is just next to the pot and the exact same fish is doing fine there. When I transfer it over, it dies.... just very confused..

Looks like Ammonia might be the culprit. Will cycle the tub for a wee bit longer before introducing more fishes...