turkish ann said:
hi aquanut,
my tank is fairly big, but its like anything when you startout, a bit green and I liistened to the guy in the shop, he said they were peaceful fish and did not grow too big, some of them have not got a clue, its hard to find a good aquarium shop that know what they are talking about and are honest with you!
It sounds like your tank isn't cycled, and neons don't cope well with an un-cycled tank. Possibly they died from ammonia or nitrite poisoning and then got eaten.
Have you checked your water parameters for ammonia and nitrite? If not, you need to do so urgently.
If you are new to fish keeping please read my article "Avoiding New Tank Syndrome" (link in my sig) before you do another thing, particularly buying new fish.
Whatever the results, do an immediate water change. If you could give us further information it may help:
1. How long have you had your tank.
2. Is it fully cycled? (if you don't know the answer, please refer to my article)
3. How big is your tank? (in litres or US gallons, or even dimensions - we can work it out from that).
4. What type of filter do you have and do you have live plants?
5. What are your water parameters (ammonia, nitrite, nitrate, pH, KH and GH).
6. What does the "green stuff" look like?