SCP Foundation

pure energy

Fix that. There is no such thing, and it won't be long before someone less friendly than I brings it up.

in containment for ██ years and show no signs of deteriorating.

Unneeded black box. Trust me, I've been shot down for the same thing.

6 serious injuries and █ fatalities

Equally unneeded and relatively unambiguous - it's 1 to 9. And the number of deaths is not a secret, especially if injuries are listed.

Aside from that, needs some proofreading.

Not sure why you need the factory reference here. It doesn't really strike me as factory, and seems more just like a one sentence connection to increase the popularity a bit. As well, the sentence "It is probable that they were genetically engineered." is unnecessary

Also, the details about how the bulbs maybe anomalously lower the resistance of water seems a bit unnecessary. What does that add, really?

I remember seeing the image with the fish being "SCP Fuel." I was expecting something like this, but not bad.

I like :) some good ideas there, definitely.
The whole thing about 'converting their bodies into various forms of energy, yet still retaining their shape and possess the ability to levitate' seems a little bit whacky; partly due to 'forms of energy' being what: heat, electromagnetic, sound, kinetic, potential…
[it's like saying: "they convert their bodies into food" - well what kind of food? steak? bananas?]
I think a little bit more specific detail on this would clarify it.
Idea: the fish convert their bodies into various forms of energy, into an entity that has a 'shape' identified by a heat imprint/sound source/light source corresponding directly to the initial shape of the fish.

Might just be me being picky and stuff, that bit just seems slightly out of touch (as if you wrote it without any second thought) since everything else seems so scientifically explainable and believable.

+1 though, nice job!

I think this tries to do too many things at once. I'd see Conservation of WTF for a better explanation of this, but you should pick one or two really weird aspects of this that you'd like to emphasize and explore them. Also,

though they share 96% identical DNA. They possess no digestive tract

I get the weird feeling that you'd need to change more than 4% of something's DNA to get rid of a full digestive tract (although I might be wrong). Which is why that's where my suspension of disbelief failed. That, the aforementioned weirdness problems, and the Factory link are why I'm downvoting this.

In addition to making changes based on Incendio and Scantron's input, I'm considering changing the name to "Electric Goldfish".

Glad to see this is doing well. Would have flagged up the 'pure energy' thing if I'd noticed during proofreading: I see what you're going for and 'various forms' is probably as good as you're going to get without writing an entirely new paragraph explaining why they think it's energy despite having a (presumably) distinct shape. 'Electric Goldfish' sounds good for the title if you did want to change. I like the mention re replacing the goldfish with a regular one - is that new?
+1

When the electrical current reaches greater than 70 amps, the creature begin emitting gamma radiation as well as light.

Um… I might be mistaken, but gamma radiation is light, isn't it? If you meant “visible light”, could you perhaps clarify that?

I don't like it. Some of the writing needs work and the idea isn't that interesting.