Disappearing Danios

I started out with 6 danios in my tank and over the last 2 weeks the number keeps going down. I'm at 3 now, there were 4 2 days ago. I checked the filter and they aren't dead in there so someone must be eating them. The only fish I have that seems big enough to eat them is a 6 inch pleco, Is this a common thing? and is there anything i can do to stop it? The pleco only comes out from under the rocks at night and thats when they go missing so he has to be the culprit, I would just like to know if there is something i can do to keep this from happening.

The pleco may not be getting enough to eat and may be sucking the slime coat off the sleeping fish. If you put in an algae wafer after turning out the light, the pleco will get his appetite satisfied in a less harmful way. On the other hand, some dinos are fast swimmers, and it could be that they are getting sick and are being eaten after they die. It's not a bad idea to check the water parameters and make sure there is no ammonia or nitrite in the aquarium. If there is, the cure all is a series of partial water changes.

Please let me know if any of this helps.

some dinos are fast swimmers

I didn't know you were into dinosaurs John.

Sorry, sometimes I can't help myself. In response to the actual question posted, I agree with what John said. Check your water parameters first. The pleco may not be to blame. Or at least not entirely. Do you see them after they die? I have had one jump out and turn into a crispy little fish stick.

They all seemed healthy and are very fast and active. The danios and the pleco seem to be the only ones not affected by the ick problem i've been having. I drop an algae wafer in everynight but I was thinking that he is just so big that he has a huge appetite. I just took the two remaining danios and put them in another tank so they don't disappear too. I'll stick with larger fish in that tank i guess. Thanks.

water quality is good too, just checked it and everything is where it should be. Nitrites were slightly elevated but not high, no ammonia or anything.

Those thunder lizards in the aquarium can indeed be jumpers. When determined, they can get through a very small space. The same goes for zebra fish.

If there is quite a bit of loose material on the substrate, the pleco may be stirring it up and somehow changing the water chemistry. One last thing about ammonia. The test kits use one of two different types of reagents. One of those reagents will not work if you have used a chemical ammonia eliminator.