If in the US there are codes local, state, and federal that clearly state not to daisy chain extension cords, surge protectors, etc. Also they clearly say what should and should not be used in surge protectors(for example you can't put a space heater on a surge protector). As noted above it comes down to amps, circuit breakers, and in the end fire hazards. Let us say something bad does happen and you are renting and hurt others? Or that same bad thing happens and damages your house. Or again same bad thing and takes out your house and the neighbors. Local fire department will investigate, they have to, and report it. Now we have to talk to the insurance company and possibly any other legal teams depending on how it unfolded.
I'm not going to get into he said, she said, or what you should or shouldn't do. If you are asking the question you are clearly aware then so already past first base and onto the next which is good. Typically unless the room is built specifically for your hobby most rooms won't have enough outlets by default for use. So it does lead one to being creative. Controllers come into play here with their controllable outlets (noted with amperage warnings of course by their legal council) that can help. Surge protector also helps although see my note above. You could use a longer surge protector into another outlet. You could also hire an electrician to add an outlet or if you are not sure at least ask them your power use vs. the breaker it is on.
It is a bit janky now with tank size, location, heater(s), number of power heads, power head size, return pump, skimmer pump, and then anything else you throw in to make your tank successful or fancy that tech itch you may or may not have. I personally went with Neptune Cor 15 pumps for my skimmer and return so I free up a plug. I also went with Apex for their new energy bar so I can see amperage to some degree and also use the outlets. Sea Swirl and Apex are plugged into the outlet in the wall. My reef angel controller for lighting is plugged into a different outlet. So all in all I'm ok but it did make me think about where I put stuff and wire / cable management.
Oh - also recently moved into a new home built in 2015. I couldn't fire out why the room my tank is in kept having its circuit breaker trip. I'd reset and sometimes it would trip again in minutes. I added a kill a watt meter to see what the tank was using, its pumps, etc. Well under the 15 amps. pulled each plug, checked plug connections just in case electrician didn't set firmly. Everything was good still tripping. Removed panel on the circuit breaker to check that wiring and again all good yet still tripping the tank at random times. Rolled out an extension cord to another plug in the house and connected stuff and it didn't trip. Now I'm lost. Called an electrician out, explained the problem, he looked at the room, the tank, my computer, said nope - nothing here is tripping it but he thought it was the new Ca building code and the smart circuit breakers causing the issue. The breaker ended up tripping when the heater turned on/off suddenly or when my wave makers over lapped. The breaker's internal computer brain that isn't so smart shut it down due to the increase activity or wave pattern because that is what it thinks when something is shorting out. At least that is how I remember the electrician explain it. Gets a lot of complaints in the area with tank owners or owners of certain stereo equipment...
Anyway more than what you wanted to know.
