You mention that there were sparks and a concern about your ground, I'd check for an incorrectly wired outlet as a precaution. The initial check is a simple outlet tester. These have 3 lights and quickly identify a hot ground or swapped neutral/hot, along with other common issues.
What they can't identify is if there's voltage on both the neutral and ground, for that, you'll need a known good ground and a simple voltage tester. For a known good ground, you can find some plumbing lines that are grounded, or perhaps the ground rods that the panel connects to, but a really easy way is to plug a long extension cord into a friendly neighbor's house and use the ground pin (in your case, the bedroom is probably a good ground). Check if there's voltage between the known good ground and your ground, or your neutral.
Since you're seeing actual sparks, I'm going to rule out phantom voltage from running an hdmi near electrical wires. And since the problem happened after you moved the TV, either the TV was damaged in the move, or it's another device that you added to the mix. Start with the outlet to be safe, but if that's not the problem, you likely had a faulty device. Given the reading of over 300V, I'm guessing that it was a faulty device. A hot/ground short would usually trip a breaker (unless it's not really grounded) and only read 120V.
Breakers and fuses are sized to limit the fault current that can flow. Each is sized to limit the current to that which the cable connected to it can safely carry. For example a 32A ring main circuit will protect a 2x 2.5mm2 cable ring circuit. Another example will be the 6A lighting circuits. These could be a single 1mm2 cable (though 1.5mm2 seems to be more commonly used).
You aren't expected to be running everything at capacity at the same time. Just because a circuit can supply a given amount of current doesn't mean that it will be doing. As long as the current draw at any point doesn't exceed the capacity of the fuse or breaker protecting it, it won't trip.
You mention 3A and 5A "plugs". This is the current above which the fuse in the plug should blow (at some point - fuses have different "trip times" for different overcurrent ratings). The appliance supplied by these won't normally draw the current marked on the fuse. For example if you had a 1W appliance, it would be likely to have a 3A fuse (the smallest common fuse for a UK 3 pin plug), but would only actually draw around 0.004A. You could technically therefore connect around 3000 of these 1W appliances through one 13A fused plug without a problem (practically however, you might find it more of a challenge...).
The important number to be considering is the total power draw (wattage) of the appliances in use at any one time, not the total of the fuse ratings.
In relation to you aquarium, as long as you don't overload the ring main, you'll not have a problem. If you total up the wattage of all your equipment, you can run approximately 3000W through one 3 pin plug. (Note though that it's common for double sockets to be rated for less than 26A, but it's not often marked on them). Your 32A ring main is therefore capable of supplying a bit over 7000W.
In the worst case, you could always have an electrician install a dedicated circuit to supply the aquarium equipment.
Best Answer
According to my calculator 1425 watts at 240V is 6 amps, well within the 13-amp limit.
Are the round-pin 16 amp plugs standard in kitchens in India? If yes, that's probably why it has that particular connector. You should be able to get a 13-amp fused plug at any hardware store.