Taros are some of my favorite plants. They do well in either well drained wet ground or in the pond. I have mine in the top of the Skippy or in a larger utility or decorative pot with drainage holes on a shelf. I can control how deep the plant pot sits by filling the outer pot with river rock to the level I want. The rim of the outer pot is just above the surface so no stray food or fishies get trapped in the crown of the plant. Don't cover the crown with water.

They grow naturally in rough clay but do well in pea gravel, hydroponic pellets (fired clay), Aquatic "soil"(fired clay granules), even peat moss but avoid peat for the pond since it will leach tannic acid into the water. Avoid soils that have perlite or styrofoam in them. It floats and makes a mess. Unless the plant is ripping the sides of that 5 gallon pot to shreds or is a very small plant in a too large pot, it will do just fine as is. Almost any fertilizer (especially for bulb plants) will do. I add it to the pot, not the pond. The mesh pots do for an outer pot but the roots will pretty much destroy them and make it hard to winterize the bulbs.

The double potting slows the water flow which taro seems to prefer.

Just an fyi on the mesh baskets - try OSH if you have one near you. That's where I buy mine. They also have the aquatic plant medium. I have found their prices to be the same if not a bit less than the big box stores. I've never seen them as large as 5 gallon so I would do as sleepless says and leave it in the original pot.