LEDninja has summarized pretty well, just some more detail to flesh out what he said...
First, the UV isn't TOO high a concern as thick aquarium glass (and water) will probably block the majority of it (but if it leaks from under the hood, that could be an issue, or reflectance off the water surface when looking in for feeding/cleaning, etc)... never hurts to be safe though either way. If you are getting enough UV from the fluorescent, then a matching amount from the LEDs won't behave any differently (it'll be just as dangerous, or safe, so long as the spectral range matches).
Those are terribly inefficient LEDs, a modern Cree running at 350mA, putting out over 100lm (as ninja mentioned, the OP LEDs are probably 3-5lm max per LED), will run in the low 3V range, even at high current (1A) the latest batches commonly run under/around 3.5V.
What that all means, if you have one white Cree LED at 350mA putting out 100lm of light at 3.2V, you have 100/.35*3.0 = 90lm/watt.
To achieve 90lm with the 5mm LEDs, at say 3lm/LED, you would need at least 30 of them. 30*.024*3.4=2.448 watts. So 2.5x the power (and a lot of extra heat going into the room), and a LOT of work (to wire up 30 LEDs properly), can all be replaced by a single good quality high-power LED.
For 5000lm (100w fluorescent estimate from ninja, actually seems low (fl are typically 80% efficient, but that's fixture and bulb-style dependent, so 50% works for this example), you'd need 50 high-power LEDs (at 350mA, fewer at higher current inputs, but heat-handling rapidly becomes a challenging design issue)... or roughly 1667 of the LEDs mentioned in the original post... just things to consider.
Also, 5mm LEDs (especially cheap ones) tend to rapidly degrade under constant usage, within months (or faster) you'd be losing double-digit percentages of output, necessitating MORE LEDs and more power, to stay equal to a good power-LED, or your fl bulb...
Bottom line, it's not feasible with 5mm LEDs, and even with power LEDs it's a challenge, if you get good heat handling, a Cree white LED, at 1A, will put out ballpark 250lm. We need 5000lm to match the bulb output, so you'd need 20, at a minimum. Power would be roughly 20*3.5*1=70watts, so not much power savings, considering the inital cost of LEDs, plus heatsink(s) design, power drivers, etc.
There are multiple LED design options, some better at heat handling, some higher-output per unit, but overall right now high-output LED tech is at roughly 80-100lm/watt no matter the other design parameters.
Fluorescent bulbs in optimal designs also run around 80lm/watt, so best case scenario, you can replace fl with LED and get EQUAL performance for "general" lighting. If directional or custom lighting is needed, then LEDs are more easily customized, putting light where needed, but for simple "tube replacement", they aren't any better today (except of course that fewer hazardous materials (mercury) are used, and relatively shock resistant with typically longer lifespans).
Ultimately, don't replace any working Fl/CFL bulbs with LEDs unless it's a design or maintenance consideration, as that is actually detrimental to the environment and your own costs (you don't gain anything significant, but you've tossed something that was already produced (damage already done), and replaced it with something else produced (doing additional damage, to the wallet, to the environment for production/materials, etc), for no significant gain, so it's a ultimately a loss). If/when your Fl/CFL dies, THEN consider replacing it with LED tech at which point it is no longer a loss (you have to replace with something at that point). By then LED tech might be better (it's improving steadily the past few years), so if your FL bulb lasts another year, your efficiency might be 110lm/watt for LED, instead of 90 today, and you've maximized the return on your investments.
but it's for a saltwater fish tank where the coral needs a certain intensity of light to sustain life. I think 100w of flourescent light is more than enough for coral, if that gives you any info to base it off of.
