Bad Wolf

I have 30 molly fry and 7 guppy fry in a 7 gallon tank. i have about 5-8 of the mollies that are about 14-15 weeks old and they are still less than and inch long.

is there any way to speed up their growth?

will giving them salt increase their growing rate?

is it good to give adult and fry live bearers salt? do they like salty or fresh? if so, how much salt? i have rock salt, is that good? or bad?

if i turn the temperature up/down will they grow? the temp is set to 27C (80F) but the thermometer says 28 or 29. the heater is 55 watts.

what should the pH be? i set it to 7.5 a week or 2 ago and now it's back to 7.

any other suggestions?

remember, there are guppies and mollies in the tank.

thanks

aquarist48

Good morning. Salt will not increase the fry growth rate. I wouldn't add salt just because you have it. If the fish were ill I'd research the species and see if they are salt tolerable. Too, if it doesn't say Aquarium Salt on the box I would not use it personally. Let nature take it's course as far as the fishes growth rate.
Your pH levels can be adjusted by water changes. How did you "set" the pH to 7.5. Chemicals such as pH up or pH down are not recommended. Too risky and unstable.

Bad Wolf

i adjusted the pH by using they pH up, only cause the tap water at my places is a bit acidic. it comes out at 6.3 - 6.6 and i know that mollies like a pH of 7.5, and i did have mystery snails for but i know they hate an acidic pH.

i plan to do a half water change every 2 - 4 weeks. will that help with the growth? i would do a 30% water change every week if it weren't for the darn water restrictions here.

aquarist48

Keep an eye on your pH levels and don't be surprised if you have to add the pH UP every day for the life of the tank. Here is a link for you, maybe you haven't seen it and it will help concerning maintaining a proper pH without the use of chemicals. These types of chemicals can be very unstable and cause pH to crash.
http://www.ratemyfishtank.com/articles/107

I'm not aware of anything that can be done to speed up growth rate of fry. I say let mother nature take its course. Good luck and enjoy your fish!

TedsTank

The more space you have the better....or frequent water changes will help the grow a bit faster...and/or maybe an airstone.....you have a lot of fry in that tank.

I was told (don't know if true) that the fish secrete a hormone that will slow their growth (or stunt if left too long) to better fit the enviroment. Something slows it and it is adjusted to your tank size.

So water changes and airstone will dilute the hormone and they will continue to grow. at a normal rate.

Bad Wolf

yes, the hormone thing is correct. i know about it, that's why water changes are very important. they secrete a hormone that is their personal smell and if they continue smelling it they know they are in a restricted area. in the wild they would have plenty of space and they wouldn't smell their hormone or another fishes in the same place all the time.

by doing water changes you are getting rid of the old hormones, then when the water is replaced, they don't smell their own hormones then continue growing until they smell their hormones again.

some people did a test on this. they got two 5-6 inch tall angelfish, they 1 in a 55 gallon tank and did a 25% water change every 2-4 days. the other angelfish was put into a 55 gallon, but they didn't ever change his water.

after a few months (i think it was nearly a year) the one that got a 3 water changes a week got about a foot tall (not including fins) and the other only got to about 8-9 inches tall.

i would do a 30% water change every week if it weren't for the darn water restriction AUS has. i did a 65% water change on Sunday.

thatnks

Bad Wolf

yes, the hormone thing is correct. i know about it, that's why water changes are very important. they secrete a hormone that is their personal smell and if they continue smelling it they know they are in a restricted area. in the wild they would have plenty of space and they wouldn't smell their hormone or another fishes in the same place all the time.

by doing water changes you are getting rid of the old hormones, then when the water is replaced, they don't smell their own hormones then continue growing until they smell their hormones again.

some people did a test on this. they got two 5-6 inch tall angelfish, they 1 in a 55 gallon tank and did a 25% water change every 2-4 days. the other angelfish was put into a 55 gallon, but they didn't ever change his water.

after a few months (i think it was nearly a year) the one that got a 3 water changes a week got about a foot tall (not including fins) and the other only got to about 8-9 inches tall.

i would do a 30% water change every week if it weren't for the darn water restriction AUS has. i did a 65% water change on Sunday.

thatnks

Nick G

They will still need a bigger tank to grow though. I just went out and bought a 40 gallon tank that is only for fry, as even in my 20gal the fry weren't growing fully.

Bad Wolf

oh, oh dear. that's a bit of a pickle. what should i do?

Sorry i did two post, my computer is crashing because of slow internet.

TedsTank

Glad to hear it is really a hormone and not an urban legend.....but changing water does work....first learned about it on my koi pond....I change 25% every couple of weeks....koi growth difference was dramatic, after regular changes.

Bad Wolf

that's good to hear.