CichlidFish.com - Fish That Think.

my rd stay's in his cave almost the whole day.but it does eat food.also it takes out all the sand and stones from it's cave.it's currently in a 15g aq.does this mean that its going to lay egg's???.even if my rd does come out,it goes back to its cave in a jiffy.there aren't any other fishes in the aq.

well if it's in only a 15 gallon aquarium then it can't be very big yet so maybe it's just instinctivly avoiding any "large preditors". If it is small enough to fit in a 15 gallon aquarium i don't think it's even able to lay spawn yet, and seeing as it's the only one in there makes it even more unlikely.
But I do hope you know that red devils get to be VERY LARGE AND WILL NEED A MUCH LARGER TANK but hopefully you already knew that and have started saving up for one already.

Please give more info
size of RD
Your water test results for ammonia,nitrite and nitrate..
If its just a young RD, they can be shy but that dont last long as they mature.

Like GW they get big and very mean and need a huge tank.. I have one in a 300litre and he is a very destructive mean fish that wont tollerate other fish...

Also RDs love to dig,, mine makes huge gravel mountains, so any decor or plants are no go.