My phone fell into some water last night (about a half foot deep for no more than 5 seconds). I powered it off and followed instructions on apple support and it turned on fine and works as of right now. Is there any chance that there is still water damage and the later on my phone could malfunction and stop working? If so is there anything I can do to prevent it or get it fixed?
Yes, there is a chance that the phone will stop functioning properly. The Apple One (1) Year Limited Warranty does not cover liquid damage, so unless you have one of the AppleCare+ Plans for iPhone, you're likely looking at an out-of-warranty replacement. You don't mention the model, so you can look up the cost here: Other iPhone repair costs - Apple Support
Yes, there is a chance that the phone will stop functioning properly. The Apple One (1) Year Limited Warranty does not cover liquid damage, so unless you have one of the AppleCare+ Plans for iPhone, you're likely looking at an out-of-warranty replacement. You don't mention the model, so you can look up the cost here: Other iPhone repair costs - Apple Support
Yes there is a possibility water and electronic don't mixed. What may work now may not down the line. Should've powered off put the phone in a bag of rice or silicon gel for at least 7 days
There is no prevention or fix - you purchase a new phone.
Possible Water Damage?
