nmonks
A stroke of the brush does not guarantee art from
I've got a topic about sand somewhere on this forum. The risk of trouble from anaerobic decay is small, but you should make an effort to keep the sand turned over. If you don't have plants with roots, keep the sand shallow (< 5 cm) and give it a stir periodically. Melanoides snails make a superb addition to such aquaria, working like earthworms to keep the sand clean and moving.
Plant roots carry oxygen, so if they are growing healthily they should prevent anaerobic decay become a major problem, even in tanks with deep substrates.
In a tank with spiny eels, I'd recommend a thin layer of sand, and only epiphytic plants (Anubias, Java fern) and floating plants. These won't be disturbed by the eels. Floating plants are extremely useful because spiny eels tend not to jump out of tanks with such plants. Some species also spawn in floating plants.
The black stuff is most likely iron sulphide.
Cheers, Neale
Plant roots carry oxygen, so if they are growing healthily they should prevent anaerobic decay become a major problem, even in tanks with deep substrates.
In a tank with spiny eels, I'd recommend a thin layer of sand, and only epiphytic plants (Anubias, Java fern) and floating plants. These won't be disturbed by the eels. Floating plants are extremely useful because spiny eels tend not to jump out of tanks with such plants. Some species also spawn in floating plants.
The black stuff is most likely iron sulphide.
Cheers, Neale