Can most SW fish tolerate 30 C / 86 F temperature?

[Sirirot]

Due to a hot weather in my country, I plan to set up another fish only tank but I don't to buy any chiller. The temperature of the water is around 30 C / 86 F degree. Is it ok for most fish?

 

[DaveK]

I'd say that's at the outside limit. Don't try to overstock that tank and you should be fine. Also check to see what your local aquarium stores are doing.

 

[Nobbygas]

I've scuba dived off the coast of Sudan, around the old underwater spots made famous by Jacques Coustou (?). Water temperature there was around 31 degrees. Didn't need a wet suit, just shorts and t-shirt, even down to 30 metres. The corals were stunning, and the amount of fish was incredible.
Just saying.

 

[Oxylebius]

Almost every organism has a range of environmental parameters where they can survive. This includes the prime conditions where the organism can thrive and the outer limits where the organisms is just surviving. I mention this b/c 86 degrees is at the higher outer limits for many ocean species (there are exceptions). You may get a few fish or other organism that can tolerate this limit, but you will also find that they may be more stress, may have compromised immune systems where disease can take over, and shorten the life span at these limits.

Yes, there are organisms that fully live in extreme conditions where they thrive. Most of these species have genetically evolved to be able to live in these environments. For example, hydrothermal vent communities. I mention them as an example of an extreme.

As mentioned above by @Nobbygas if you plan on having species from the area described, then you shouldn't have any issue. If you take clowns and other species who are used to temps around 78-82 degrees and place them in a tank at 86 degrees, they may not do as well. 86 degrees will be at their higher upper limit and you may loose some (if not all of them). The odds are higher that you will loose life.