I know this post isnt really active anymore but I just wanted to add my 2 cents because I had a very similar experience and I think I can help you out!!! If you dont wanna read my rant thats fine, if you only read one part Id recommend just skipping to the last paragraph. I really do think my experience can help you though. For a long time i struggled with growth rate.
I had a 75 gallon grow out for my Dovii and the growth rate was extremely slow... 3 months had gone by and even though she looked better, she was not noticeably larger. I began to get impatient because I knew they should grow faster than this.
I took out her 2 smaller siblings ( now she was alone) and put a 2nd filter on the tank. I now had an AquaClear 110 and a FX5 . I pretty much used the AquaClear HOB as a water polisher. I filled it with filter floss and put metal rods in there to hold it down. It made the water sparkle. Before, even with a FX5, thered be little bits of debris and slightly murky water sometimes from her messy eating... adding the HOB strictly for water polishing made life easier. Caught all the tiny stuff making the water murky. Putting water polishers in the FX5 clogged it within a few days....the HOB is so easy to empty and refill with fresh floss...plus I can see when its soiled.
Then I started actually doing water changes, I did before but it was once a week,,,maybe once every 10 days. I finally started doing them 2 times a week and shot for 3 whenever I could push myself. I also treated her tank with "General Cure", it treats for 6 different parasites I think. I had fed her baby guppies a few months earlier.
I wanted to increase the amount she ate so I got sinking Hikari pellets...she was shy and wouldnt come to the top...the sinking pellets worked a lot better. I also dimmed her light in the tank so she felt safer and readily came out to eat after that. I had to mess with her hiding spots...they were a little too good. I made it so she could hide, but could still see when food was dropped in the tank. Id shut the filter off to prevent the food from being blown around and sucked into the filter. it also allowed her time to come out of her burrow and grab it whenever she felt comfortable. She was so damn shy, Id drop the food and leave the tank. Id come back in 5 minutes, if food was gone id add a little more and repeat. If I came back and food was still there, id net it out and turn the filter back on. Water quality is paramount. I got Formula One brand frozen Cichlid cubes.... she LOVES them. Most pellets that people swear by are just trash... even beloved Hikari. Just look at the ingredients....The ingredients are listed by whatever is used most in the product incase you didnt know... Hikari Cichlid Gold:
Fish Meal,
Wheat Flour,
Wheat Germ Meal, Brewers Dried
Yeast, Soybean Meal......the list goes on.
Yum Yum, right? What Dovii doesnt love wheat flower and yeast?
Now check out Formula One frozen cichlid squares: Salmon, Whole Pink Shrimp, Whole Kelp, Halibut, Pacific Cod, Spirulina, Shrimp Eggs, Gel Binder, Vitamins (Vitamin A, Vitamin D, Vitamin E, Menadione, Thiamine, Riboflavin, Pyridoxine, Vitamin B12, Ascorbic Acid, Niacin, Pantothenate, Folic Acid, Biotin, Choline, Inositol), Garlic.
Thats almost better than what I eat!! All the fish doesnt have "Meal" after it either... its whole salmon etc. That is a HUGE difference!!! meal is just the ground up slime leftover from fish processing plants. They cute off heads, cut off skin, remove guts, send all the meat to be sold at a super market somewhere and sell the leftover guts to Hikari so they can sell it as 5 star fish quisine....
Yes, i know I said I feed Hikari and I do. Just for some variation. I also use Formula One cichlid pellets ,frozen beef heart, tilapia and dried krill.
Anyway, the point im trying to make is I try to give her meats, real meats instead of ground up leftovers that are dried and pressed into pellets.
I clean my canister filter once a week now as well., the HOB is whenever I do a WC
I know this is a lot to read, i hope im not wasting my time lol, but I had a moment where I just got impatient and frustrated and made the changes... the results were extraordinary. After 2 weeks of this new routine her colors, behavior, appetite exploded... It was awesome. She was growing like a damn weed, Id say an inch per month and before it was not even an inch every 3 months.... She was growing wide just as much as she was growing long!
I decided no more live feeders from anywhere, I set up a 20long baby guppy farm to feed my cichlids from. Now I know theyre all parasite free. Honestly, any fish you buy from Petco, Petsmart or a LFS probably has parasites. Gill flukes, intestinal, maybe even bacterial disease.....even if they look fine, theyre not healthy. Theyre all inbred and genetically inferior, add that to the fact theyre kept in depressing, overpopulated, dirty conditions I think itd be a miracle if they didnt have parasites. Poor guys
Anyway, Ill shutup now... I just wanted to help out. For a long time I read over and over to do more water changes and I always just thought it was a nonsense piece of advice people gave. something that couldnt hurt but something that wouldnt increase a fish growth rate... I was so wrong. Fish like P.Dovii release certain chemicals in their waste.... when that chemical builds up in the water it stunts their growth. This helps them to not outgrow their surroundings in the wild... Change the water as often as you can to remove those trace chemicals!!!!! Very important!! I never knew.... I promise you will be amazed!!!