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1 , \ i I Severson et al. 57 I ,. ; gen = 5.4 mg/I; pH = 7.7; total hardness = 440 mgll), and swim- up was attained by fry after five days. Fry were sample-counted and weighed (three groups of 100 fish each) to calculate a feeding rate of 5.75% total body weight per day. In the first part of this study (Phase I), fry were hand-fed a diet of BioKyowa B-250 (BioKyowa, Inc., St. Louis, Missouri) six times per day at the above rate for 20 days (days 5-25) beginning on the fifth day after hatching. The feeding rate was not adjusted dur- ing Phase I because of the small size of the fish (average weight = 0.005 g). On day 20, fish were weighed to determine the average amount of food consumed. Phase II of the study was initiated on day 26 and ended on day 52. Twelve groups of 100 fry ~ere randomly selected, weighed, and placed in mesh-bottomed PVC tubes (diameter = 20 cm) that contained 3.81 of water. Each tube was suspended in a 29.1-1 com- partment and supplied with heated, degassed, aerated, single-pass well water (flow = 2 l/minute; average temperature = 20.0oC; average dissolved oxygen = 6.0 mg/I; pH = 7.7; total hardness = 440 mg/I). Water exchange between the tank compartments and the pve tubes was through a screened bottom and side slots. Well- . water was introduced into the top of each tank via an overhead pipe system, and tanks were drained by surface standpipes. Three repli- cates of each diet were randomly assigned to the twelve experimen- tal units. During Phase II, four diets were hand- fed six times per day at a daily ration of 10% total body weight. The fish were weighed for feeding- rate adjustments at 2-week inteavals. Diets tested were: Bio-dry starter #1 (Bioproducts, Inc., Warrenton, Oregon); AP-IOO (Zeigler Bros., Inc., Gardners, Pennsylvania); BioKyowa-A (BioKyowa, Inc., St. Louis, Missouri); and Silver Cup Salmon Starter (SCSS, Murray Elevators, Murray, Utah). All diets were subjected to proxi- mate .analysis (Association of Official AnalyticalChemists 1984). Proximate analyses of the diets are shown in Table 1. Phase III of the study was initiated on day 53 and terminated 74 days later (on day 126). This phase had five experimental units consisting of 25-cm PVCtubes containing 7.58 I of water that were suspended in the same 29-1 compartments. Flow rate was increased j j I j .1 :/ . ~t~ ~~\'~~'~ . J;