Just got 4 madagascar hissing cockroaches

[pacoparrot]

I was up at a new pet store today and I bought 4 nymphs. I'm hoping for at least one female and one male. These ones will be pets not breeders but their offspring will be for Chomper. How long do they usually take to grow to maturity? I'm giving them flucker's calcium gel drink and flucker's cricket food, ground dog/cat food, and goldfish flakes. They are in a 5 gallon tank with a 3" thick olive oil line around and soil substrate. Anyone have any ideas on how I can heat them without light? Will the light bother them, I have a light fixture set up for them but I don't want it to kill them? I don't have a heating pad or heating tape.

 

[DragonLuver211]

I use a cermic heat blub thing from the pet store goes in your light fixture