Mass-effect – Fulfill a Krogan’s dying wish

For a whopping 25,000 credits, the Aquarium VI is available for sale on the Citadel, at the Elkoss Combine Arsenal Supplies terminal (where you first find Barla Von) in the Presdium Commons.

In addition to breaking your piggy bank, this pricey item's description also indicates that it will automatically feed your fish:

With so many exotic speices of fish available in today's galactic market, it takes an expert to maintain an ideal aquarium. This VI automatically dispenses food, adjusts the temperature, pH, and algae content of the water, and even talks to the fish when you're not around, leaving you free to enjoy your aquatic friends without fear of killing them.

If 25,000 credits isn't expensive enough for your tastes, you can also head on down to the Alliance Requisitions terminal in the Normandy's cargo bay, where you can buy the same Elkoss Combine Aquarium VI for base price + a 2,500 credit markup.

In general, the only time dying has permanent consequence on the game (other than the obvious fact you just died) is during events that have been scripted to have an effect.

Examples include Shepard dying at the end of Mass Effect 2 if things went horribly, horribly wrong, during the "survive 5 waves" event of the Arrival DLC, the non-standard game over if you don't escape the Reapers during scanning in ME3, etc.

Otherwise, the game does not keep track of your deaths in a way that would have a meaningful impact on the game. In general, avoiding death is in your best interest for obvious reasons (quicksave often!), and if your death is going to have a meaningful impact on the story, like during a scripted event, you will notice it.