I chipped in on this a long time ago called the EcoCube C from a company called ATI.
It has worked great. My fish is named Zoidberg. For the longest time I've had the top cracked open so i could have the 14 day feeder I bought drop stuff in regularly for him to eat.
Anyway - now that I have my Glowforge I decided to build a top that took the feeder into account because leaving the top that they included with the kit that far open made the water evaporate very quickly.
Anyway, couple shots of the build...
1. this is what the top looks like - on the left the pegs have "feet" that allow it to "grip" the edge of the tank so that the weight of the feeder does not allow the top to tip and spill the innards of the feeder. The feeder support is hollowed out with the x cross hatch there to give it strength but reduce weight. The four pegs keep it aligned in the glas from front to rear sliding in case the top is knocked by a human by accident.
2. detail of one of the "feet" of the top - the cylinder/peg that joins the top and the foot is pressure fit into the top and the foot. It is precision cut with the glowforge - took a bit of time to understand the kerfing effects of the laser and how much material was incinerated on the left and right of the center of the beam but now it is a tight pressure fitting on both sides.
2) To put on the top you just angle the feet in and place it down sliding from right to left to allow the feet to grip under the ledge of the cube.
3) the 14 day feeder form fishmate sits on the extension and the hole for the food to go into is under the one drop through hole for the feeder.
4) tada - 14 days of food queued up.
5) My fish, named Zoidberg. I think he approves.
Anyway - I was amused because it had been on my list of things to do someday and someday turned out to be today.