---
title: "Aquaculture: problems we treat | Alchemal"
url: "https://alchemal.com/aquaculture/problems/"
description: "The problems we treat in hatcheries, raceways, and grow-out ponds, what is actually happening in the water, and what usually fixes it."
source: "Alchemal — alchemal.com"
---
# What goes wrong in hatcheries, raceways, and grow-out ponds

Each page explains what is actually happening in the water, what usually fixes it, and when oxygenation is not the right tool.

7 problems

## What are you seeing?

- [Black pond bottoms in shrimp culture: the anaerobic sediment A pond bottom gone black and sour, with soft-shelled shrimp and thin survival. See how oxygen to the sediment keeps the bottom aerobic.](https://alchemal.com/problems/black-pond-bottom-shrimp/)

## What are you losing?

- [Morning die-offs: the pre-dawn oxygen crash Stock lost overnight, found at first light. See what causes the pre-dawn oxygen crash and how a continuous reserve prevents the next one.](https://alchemal.com/problems/morning-die-offs-grow-out-ponds/)
- [Low dissolved oxygen: the ceiling on stocking density Feeding harder for gains that don't come, with the pond closer to a crash each night. Oxygen is usually the ceiling. See how to read the headroom.](https://alchemal.com/problems/low-oxygen-stocking-density/)
- [Fish that eat but don't grow: feed, oxygen, and FCR Feed going in without the weight coming out. When oxygen is marginal, the stock converts poorly. See how steadier oxygen returns energy to growth.](https://alchemal.com/problems/feed-conversion-slow-growth/)
- [Hatchery and raceway oxygen: the flow-through margin Dissolved oxygen falling pass to pass, the last raceway running short. See how efficient oxygen widens the flow-through margin.](https://alchemal.com/problems/hatchery-raceway-oxygen/)
- [Biofilter oxygen and ammonia in RAS: the nitrification link Ammonia creeping up while the biofilter looks healthy. Nitrification is oxygen-limited. See how steady oxygen lets the biology keep pace.](https://alchemal.com/problems/ras-biofilter-oxygen-ammonia/)

## Tired of treating it?

- [Living on paddlewheels: cost, coverage, and the outage risk Paddlewheels running long hours, more added every season, one outage from a bad night. See how a held reserve changes what the machines must carry.](https://alchemal.com/problems/paddlewheel-aeration-dependence/)

## Tell us what your water is doing.

A specialist reads your description and replies in writing: what it usually means and what we would measure first.

[Get a free assessment](https://alchemal.com/assessment/)