wow your both telling this person to ignore the ph lvl that rather immature sounding to me if you look at acceptable ph ranges for the fish they have there are overlapping margins but none the less to say that they will merely adapt to a ph is a bit off key dont you think ? especially hearing you talk about the fishes individual needs by the region they come from, granted i obviously know a heck of a lot less than most being relatively new to this again now but i know some fish have a wide range like the catfish for instance. but i also know the the angel calls for ;ike 6.5-6.8 th be healthy so adaptation or not if the ph is at 7.4 or higher , which is possible easily then that fish cant be as healthy as you would hope for. i didnt mean to run out in any means , but i thik its irresponsible to say to ignore it , Jshilo is corect though fluctuation to rapidly or to oftin is truly the killer among ph issues in my opinion, i do not recomend a ph up or ph down , i use a neutralizer that regardless of if its high or low it over the coarse of several days slowely balances it all at 7.0 its cald neutral regulator by sea chem. it was 5.99 at my lfs. directions calls for 1/4 tea spoon for each 3-5 gallons so me being causious to not use to much foregn chems or junk in my water i do each 5 gals so i do 1 and 1/2 tsp and it take atleast 5-7 days to bring it back but i have also never seen my own over 7.2 and only use this once a month . if you can get a nitrate and nitrite count that would be helpful which is why i say take water with to petco or where ever you go to buy ur chems thel usually alwayse try and help out , if it apears to be anything other than ph it is all easy fixes , i also use a product cald prime , its cheap and sole every where im sure you know it or have seen it. it it awesome for slime coats but it removes chlorine, cloramine , and ammonia. also it detoxafies nitrils and nitrites .. it is also made by sea chem. one capfull for each 50 us gallons or use directions for smaller dosing but i use it to condition my water in a bucket when i vaccuum and water swap so wile im vaccuuming its already conditioning in clean water. maybe give it a shot if you never have, but this is only if its needed , i dont mean it will just fix any issue , just that its a very mile low chem incredible working all in one that is safe to use at water changes weekly. adn again i hope u figure it out. but remember , if there is no chem or temp issue then it very well could have been just the fish , but without all the info i cannot say all to much more about the subject.
I have been keeping fish for more than 30 years, I know that angels come from low ph in the amazon, but unless your buying wild fish any more they have become adapted to higher ph. When speaking of regions I was talking about the different dietary needs of the fish, most malawians are herbivore and can't tolerate a protien diet. It causes a disease called malawi bloat.
Most fish can adapt to any ph as long its not fluctuating. I have seen angels thrive in a ph of 8.9, but they won't breed.
When it comes to wild fish, I would never advise them for in experienced people because the the different needs and harder to keep alive. Most fish in the trade are mass produced in conditions less than desireable and most are produced in waters outside of their natural enviroment, unless you get them from a private breeder.
Most big box stores like petco and petsmart uses the test strips which are really unreliable, Its best to use a liquid test and do it on your own. I know I have tested it out. I have even taken some bottled water to be tested and was told it had high ammonia and high ph. Bottled water is neutral.
Oh and I also keep and breed angels at a ph of 7.4 and they do fine. I also have wild caught plecos that I keep at 6.5 (but they are wild caught)I don't use chemicals to lower my water but I do it naturally with aldercones, oak leaves and lots of wood.