You know the big, rectangular bricks of Haddock? They're actually kinda interchangeable with Scrod (funny how they're allowed to call fish something when it isn't what it says.)
Thaw two of those. Put them in a glass cake pan. Butter on top optional. Actually, thawing is optional, but recommended. Now, grab about half a sleeve of Ritz crackers and crumble them on top. Microwave (don't bake... trust me) for a few minutes until barely done. Lemon juice only after cooking if desired. Lemon juice can make the texture of Haddock a little bouncy if you add it before cooking.
Most important part... remove from the baking dish before serving. What ends up in the bottom of the pan is this milky-looking water with disintegrated chunks of Ritz crumbs.
What you end up with is the world's fastest, cheapest fish dish. The big flakes of Haddock are reminiscent of Sea Bass if cooked properly. Haddock is really a fantastic fish that doesn't end up tasting fishy. Light flavor, easy to cook without messing up.
Tilapia responds very well to a Piccatta type recipe. Pan-fry some flour-dusted Tilapia in a tblsp of oil. Take the tilapia out and add some diced shallots. Saute' for a few minutes until soft. Add a bunch of lemon juice, capers, and salt/pepper. White wine if desired. Reduce until slightly thickened and pour over the fillets. The shallots are a nice touch, but totally unnecessary if you want to skip that prep/cook time.
Salmon is so forgiving. It holds up to so many flavors. Try baking it sometime using equal parts of any marmalade and soy sauce. You can really use any sweet, but if you don't have the zest from using marmalade, just add some balsamic vinegar, lime juice, apple cider vinegar. I just did some last week with peach preserves, lemon juice, some red pepper flakes, and soy sauce. Equal parts honey and soy with garlic makes a dandy teriyaki.
Does she do Tuna? Swordfish is another one, but I'm terrible with swordfish. It's one of those that seems to go from medium rare to bone-dry grainy leather in a split second. Tuna is so good rare that it makes it easy. Marinate in something for a few minutes. Dredge in sesame seeds, then sear it with a hot skillet for a couple minutes per side. If you sear it long enough that the edges keep a tiny bit of pink, it will finish without the pink edges, but stay rare-medium rare inside.
Really wanna up your game with the fam? Buy a whole snapper or Barramundi. Stuff the cavity with every fresh herb you have in the garden. (ok, maybe not mint or lavender). Add garlic cloves and sliced lemons. Mix up a cup of kosher salt with a couple egg whites and smear it all over the outside. Wrap it up in a banana leaf (optional). Throw in on the grill until it's done. Snapper can get dry easily, but the salt makes a kind of water barrier.