Several diseases and water-quality problems can look alike. Sudden deaths, falling feed intake or breathing distress need prompt advice from a qualified aquatic animal health professional and an appropriate diagnostic laboratory.
What it is
The underlying cause is not settled for every situation described as RMS. Infectious, environmental and management-related problems need to be investigated rather than assumed from the label.
CIBA describes ongoing work on unexplained running mortalities. A pond may have more than one problem. Do not blame the farmer or declare a particular virus or bacterium without evidence.
Signs to watch for
- A few sick or dead shrimp are found repeatedly over several days.
- Feed response, activity or growth changes; some affected animals may show pale muscle patches.
- Estimated survival or biomass falls behind expectations; counting visible dead shrimp alone underestimates total loss.
What else can look similar?
- Repeated overnight low oxygen, poor bottom conditions or chronic water-quality stress.
- Confirmed infections or nutritional problems causing a similar persistent mortality pattern.
Spread & risk factors
- The field term has no single established transmission route; the route depends on the actual cause.
- Shared water or equipment can spread an infectious contributor, while shared weather or water problems can affect several ponds without contagion.
How to confirm the cause
- Arrange an aquatic-health assessment of live affected shrimp, mortality history, feeding, water trends and pond-bottom condition.
- Use laboratory tests selected from the findings, potentially including microscopy, histology and pathogen-specific tests. A negative panel does not by itself diagnose RMS or prove that all infection is absent.
Prevention: your practical checklist
Keep daily feed, mortality and water records rather than waiting for a major crash.
Maintain reliable overnight aeration and measure oxygen at vulnerable times.
Match feed and stocking to actual pond capacity and manage organic waste.
Use traceable seed and keep pond-specific gear to reduce cross-contamination.
Plan timely professional follow-up when low-level losses begin, with records for comparison.
What to do if you suspect a problem
Start a dated pond-level record: count observed deaths, describe behaviour and record feed response.
Check oxygen promptly and review recent rainfall, bloom changes, inputs and sludge disturbance.
Contact a qualified professional for a structured investigation and suitable laboratory samples.
Reassess population and crop economics using explicit uncertainty; make harvest or containment decisions with the professional, not from a fixed “RMS medicine” recipe.
What not to do
- Do not treat RMS as a confirmed single-agent disease.
- Do not assume the same product will work in every pond or use preventive antibiotics.
- Do not ignore small losses or add many products together and lose track of what changed.
Farmer questions
Only a few shrimp die each day. Can I wait?
Repeated losses can accumulate, and the visible count may miss deaths on the bottom. Record the pattern and seek assessment early rather than waiting for a large visible loss.
The PCR panel is negative. Is it definitely RMS?
No. It only reports the tested targets in the submitted samples. Sampling quality, timing, other agents and environmental causes still need review.
Sources & further reading
Sources support the discussion above. Their inclusion does not mean these organisations reviewed or approved this article. Some references cover other shrimp species; the guide states limitations where relevant.
- 01Training manual on shrimp culture and disease management in inland saline areas — section 5.5, RMS ↗
ICAR-CIBA, December 2022; historical technical reference
- 02
- 03
AI-assisted source check: 16 October 2026, not professional approval. Reference dates refer to the documents, not their URL filenames or live disease status.
AquaGrow completed an AI-assisted technical-source and translation-consistency check on 16 October 2026. This is educational content, not an individual pond diagnosis, a prescription or an endorsement by ICAR-CIBA, NACA or WOAH. An independent clinical review has not been completed. Translations also await independent review by native-speaking aquaculture specialists.
This is a selected learning library, not a complete disease list or a statement that every condition occurs in Andhra Pradesh or Odisha. No live outbreak surveillance is provided.