Exploding what?

So, I have a director that wants to do a play called "boom" by Peter Sinn Nachtrieb. The challenge, apparently there is a fish tank that explodes... Yeah... and exploding fish tank, which also is full of water with a fish in it. I'm a designer primarily who also has to function as the TD and I have no clue on how to even approach this. I wanted to get some alternative opinions before saying no.

Does anyone have an idea of how to do an exploding fish tank?

Scrim , lighting effect , sound effect and some good stage hands.

Could also do this without the scrim.

You could try something like kinetic sand and added water. Or possibly have a ring of water around the front and sand behind, so there is an amount of water that explodes first and allows a goldfish to swim, but the ooze after the initial exploding water is the sand.
Here's a homemade kinetic sand video

Kinda feel like the sand would kill the fish. Unless you got a fake fish.

Rear projected fish?

Come on y'all, lets help the guy out before we go the easy route.

OP, anything is possible one way or another. There are ways to do it, but we need some boundaries to start whittling down the possibilities. tank size, position on stage, whats happening on stage when it breaks, is seeing the fish actually important, can the set deal with water being dumped all over it, do we need some kind of basin/drain, what happens immediately after, BUDGET, etc etc etc....

Brainstorming, but I would make up an aquarium that has maybe 1 inch thick actual water space.. fake fish or real... Build it into a shelving unit Think of the fake wall baby bottles that the "milk" drains away. have a bubbler etc to make it "real"
Now you have an aquarium that weighs 8 pounds instead of 180, and at the appropriate time... Flash of light puff of smoke... can lower the "real" aquarium into the base, and then could have a plexi "drawbridge" drop forward from behind the thinquarium and it will
dump a controllable amount of water, "glass" etc.. from the unit. Bubble curtain has been hiding the gimick "drawbridge" behind the real water. Back side of the drawbridge can be "shattered" glass edge Solves the weight problem and solves the problem of containing 20 gallons of water onstage when it blows. Can make quite a mess with
1 or 2 gallons, but much more manageble with out drains/ special flooring etc to reign in 20 gallons dumping.
I can sketch this up when I get a chance.

very rough sketch of the concept