Can't turn my sim into a mermaid

I can't really comment - I got IP only a few days ago and I haven't had a mermaid yet 😕mileyhappy:

I just tried the game made sim and it worked on the first try

How interesting. Maybe your other sim had a corrupt outfit or something - do you have CC? 

What's a CC? I didn't get any error at all, so i doubt it's a corrupt outfit.

Here is a link: http://answers.ea.com/t5/The-Sims-3/HOW-TO-Find-and-remove-bad-custom-content-CC/td-p/2759940

CC  - a.k.a. custom content - is content that you download from other sites (thesims3resources would be a good example) or from the Exchange.

I don't have any custom content that I didn't make within the game. The only 3rd party anything I'm running is that 1 mod.

I have no idea. Maybe the other helpers will know

If you do decide that your problem is solved (not that it really is at the moment), please accept a solution. Just a heads up 

if the other mer that gave you kelp has the evil trait you rsim won't become a mer a sto the evil sim it's kinda like playing a trick

is your mod up to date ? the same patch level as your game ? for example  if your game is on 1.63 and your mod is 1.55 then the mod is outdated it's good idea to have both at the same level

the other thing you may need to is clear the cache files  or edit town save a copy of the sim to the libiary star a new game in IP and try again

make sure it's mermadic kelp your sim eats not kelp

delete the cach files go to electronic arts/the sims 3/

 
•CasPartCache.package
•compositorCache.package
•scriptCache.package
•simCompositorCache.package
•socialCache.package.package

it's safe to delete these files as a new ones will regenerate

The mer didn't have a evil trait, and the mod was up to date with the newest version.  

Before downloading the mod yesterday I was clearing the cache. I've gotten tired of that, so I got a mod that does it automatically. 

I didn't know there was regular kelp in the game. 

yeah there is regular kelp in the game it can be bought at the grocery/supermarket if you want/need to keep a supply in your mers back back my mers have about 30 bought kelp in the back pack

oh just thought of something sometimes a save game corruption can be going on so i don't know if it was mentioned have you tried to go to edit town save a copy of your sim to the library and start a new game to see if that same sim can become a mersim