Is mushy fish safe to eat? (why is it mushy)

In this article, we will discuss whether mushy fish is safe to eat, how to identify if fish is no longer safe to eat, what are the risks of eating spoiled fish and how to handle and store fish properly.

Mushiness in fish can be caused by different reasons. Fish is very perishable and microbial activities can lead to changes in the texture. However, fish freezing and thawing can affect its texture.

Is mushy fish safe to eat?

Yes, mushy fish may be safe to eat, if the texture is the only alteration that is present in the fish. The texture of fish alters during storage due to enzymatic degradation of the proteins, or microbial activities, causing softening (1, 2).

If a fish is mushy due to microbial activities, it is not safe to eat. However, microbial spoilage of fish is accompanied by other alterations, including the formation of off-odours and off-flavours (4).

On the other hand, the mushy texture of fish can also be caused by the freezing and thawing of fish, which causes the disruption of the cells by the ice crystal growth during the freezing process (3).

Freezing and thawing reduce the water-holding capacity of the fish tissue, leading to drip loss (loss of moisture) and a softening of the fish. In this way, mushiness in fish does not necessarily mean spoilage and a mushy fish can be safe to eat.

When is a mushy fish not safe to eat?

A mushy fish is not safe to eat when it is spoiled. Microbial spoilage in fish leads to the softening of the fish’s muscles, as microorganisms produce enzymes that deteriorate the proteins, reducing their length (2).

Fish are susceptible to contamination by many pathogenic bacteria, such as Sherawella, Aeromonas, Enterobacteriaceae and Pseudomonas (2, 4).

According to studies, the growth of these bacteria during storage is accompanied by the softening of the fish, as well as by other alterations (2, 4).

How to prevent fish from getting mushy?

To prevent fish from getting mushy, you should store it in a chilling condition. Different from freezing, chilling temperatures, which are slightly higher than freezing temperatures, do not solidify water.

In this way, mushiness due to freezing and thawing does not occur and the losses of moisture and texture during storage are reduced (7).

How to identify spoiled fish?

Spoiled fish can be identified by alterations in the texture, odour, flavour and appearance. 

Off-odours and off-flavours that indicate spoilage in fish are related to the generation of oxidation products, such as rancidity and bitterness and also to the degradation of proteins, such as ammonia-like, strong “fishy” and sulfuric odours.

Microbial activities may also result in alcoholic, musty or fermented off-odours, slime formation, generation of gas and discolourations, such as red or green spots (4). Mushiness and softening of the texture may indicate spoilage as well as rot.

What are the risks of consuming spoiled fish?

The risk of consuming spoiled fish is having a foodborne illness, including an infection caused by the ingestion of contaminated fish and the ingestion of toxins produced by microorganisms (4).

The ingestion of fish contaminated by a high number of microorganisms leads to infections with symptoms such as diarrhoea, vomiting, abdominal cramps and fever (6).

Improper storage or improper freezing and thawing procedures, unhygienic food handling, cross-contamination and insufficient cooking are possible causes of contamination (5).

Another risk of consuming spoiled fish is intoxication by histamine, a biogenic amine commonly related to some species of fish.

This intoxication is known as Scromboid and can lead to gastrointestinal symptoms such as vomiting, diarrhoea, and nausea, but also to symptoms such as headache and palpitations.

How to handle and prepare fish properly?

To handle and prepare fish properly, you should always follow accurate hygienic practices to reduce the risks of contamination. In addition, some tips are useful (4, 5, 8):

  • Purchase fresh fish with a pleasant odour and bright colour with no signs of spoilage
  • Do not keep fish unrefrigerated during transportation or the thawing process
  • Store fish in the refrigerator or freezer and consume fish within its shelf life
  • Cook fish till the temperature achieves 145 °F (63 °C)
  • Do not consume fish that has indications of spoilage 


In this article, we discussed if a mushy fish can be safely consumed, how to identify spoiled fish, the risks associated to the consumption of spoiled fish and how to handle fish properly.

A mushy fish can be safely consumed if you can identify the causes of the fish’s mushiness!

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Sáez MI, Suárez MD, Cárdenas S, Martínez TF. Freezing and freezing-thawing cycles on textural and biochemical changes of meagre (Argyrosomus regius, L) fillets during further cold storage. International Journal of Food Properties. 2015 Aug 3;18(8):1635-47.


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