About two days ago I bought four Nerite snails, two tiger and two zebra. I put them into a tank my brother was using to hold other fish till his larger tank was ready and they are not active at all. I put in two algae wafers for them to eat and I don't think they touched them at all. Is it normal for them to be so inactive? I was also thinking that they might not like being on the sand thats in there. Any kind of answer to this would be much appreciated. 
