View Full Version : Larger tank=faster growth/Smaller tank=slower growth?

01-18-2010, 07:59 PM
About 5 months ago I purchased a colony of Tropheus sp. Black 'Bemba' ('Orange Flame') juvies. Most were about were about 1.25"-1.75" in length, however there were 4 in the group which were under 1.25" (maybe an inch if that).

After quarantine all but the smallest one's were added to my 125gal tank; the smallest one's remained in my 10gal for further grow out because they were edible-sized (I've got larger fish in the 125).

It's now January and the 4 tropheus in the 10gal grow out have barely put on any size and are now essentially the same size of their larger siblings were at time I got them (1.25"-1.75"). However the one's in the 125gal, have displayed an significantly superior growth rate during the same period and have gotten considerably larger and are currently at about 2.5" to just under 3".

I added the remaining four pee-wee's to the 125gal yesterday, the size difference between them and their larger siblings is just amazing (the initial size difference 5 months ago was less than an inch). In the photo the tropheus in the center is dwarfed by its larger sibling in the upper right corner:

Both tanks were on pretty much the same water change schedule (50-60% every 1-2 weeks), and similar diet (HBH Natural Veggie Flake Premium for both tanks, but the 125gal also gets NLS pellets).

I wonder if the larger tank was the factor for greater growth. If so hopefully the last four will now put on some size.

01-20-2010, 05:11 PM
That is a huge size difference. I noticed decent gains in all my fish after moving them into a 120g , but not quite as drastic as you've experienced here. I love the rocksthumbs2: .

01-21-2010, 12:05 AM
Fish excrete hormones, some of which will slow or limit growth rate. The more crowded they are (or in a smaller tank, the hormones are more concentrated) the greater the effect they'll have. Some fish don't seem to be bothered by crowding, while other species are highly sensitive to it.