Foreign investment in aquaculture is permitted without restrictions, but foreign participation in commercial fishing activites within India's EEZ is restricted to 49%.
"CHAPTER 3: GENERAL CONDITIONS ON FDI [...]
3.4   ENTRY ROUTES FOR INVESTMENT 3.4.1 Investments can be made by non-residents in the equity shares/fully, compulsorily and mandatorily convertible debentures/fully, compulsorily and mandatorily convertible preference shares of an Indian company, through the Automatic Route or the Government Route. Under the Automatic Route, the non-resident investor or the Indian company does not require any approval from Government of India for the investment. Under the Government Route, prior approval of the Government of India is required. Proposals for foreign investment under Government Route, are considered by respective Administrative Ministry/Department. 
[...]
3.5   CAPS ON INVESTMENTS
3.5.1 Investments can be made by person resident outside India in the capital of a resident entity only to the extent of the percentage of the total capital as specified in the FDI policy. The caps in various sector(s) are detailed in Chapter 5 of this Circular. 
3.6   ENTRY CONDITIONS ON INVESTMENT
3.6.1 Investments by non-residents can be permitted in the capital of a resident entity in certain sectors/activity with entry conditions. Such conditions may include norms for minimum capitalization, lock-in period, etc. The entry conditions in various sectors/activities are detailed in Chapter 5 of this Circular.
[...]
5.2 PERMITTED SECTORS
a) In the following sectors/activities, FDI up to the limit indicated against each sector/activity is allowed, subject to applicable laws/regulations; security and other conditionalities. In sectors/activities not listed below, FDI is permitted up to100% on the automatic route, subject to applicable laws/regulations; security and other conditionalities. [...]
c) Foreign investment in sectors under Government approval route resulting in transfer of ownership and/or control of Indian entities from resident Indian citizens to nonresident entities will be subject to Government approval. Foreign investment in sectors under automatic route but with conditionalities, resulting in transfer of ownership and/or control of Indian entities from resident Indian citizens to non-resident entities, will be subject to compliance of such conditionalities. 
[...]
5.2.1 AGRICULTURE & ANIMAL HUSBANDRY
Sector/Activity | % of Equity/ FDI Cap | Entry Route [...]
c) Animal Husbandry (including breeding of dogs), Pisciculture, Aquaculture, Apiculture; and  [...] 
Note: Besides the above, FDI is not allowed in any other agricultural sector/activity. | % of Equity/FDI Cap: 100% | Entry Route: Automatic [...]" (Government of India/Ministry of Commerce and Industry (2020), Consolidated FDI Policy (Effective from October 15, 2020))
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"CHAPTER I - PRELIMINARY [...]
2. In this Act, unless the context otherwise requires,[...]
(d) “foreign vessel” means any vessel other than an Indian vessel;
(e) “Indian vessel” mean:-
(I) a vessel owned by Government or by a corporation established by a central Act or a Provincial or State Act, or
(II) a vessel:-
(i) which is owned wholly by persons to each of whom any of the following descriptions applies:
(1) a citizen of India;
(2) a company in which not less than sixty per cent , of the share capital is held by citizens of India;
(3) a registered cooperative society every member whereof is a citizen of India or where any other cooperative society is a member thereof, every individual who is a member of such other cooperative society is a citizen of India; and
(ii) which is registered under the Merchant Shipping Act, 1958, or under any other Central Act or any Provincial or State Act.
[...]
CHAPTER II - REGULATION OF FISHING BY FOREIGN VESSELS	 
3. Subject to the provisions of this Act, no foreign vessel shall, except under and in accordance with:
(a) a licence granted under section 4; or
(b) a permit granted under section 5, by the central Government, be used for fishing within any maritime zone of India.
4. (1) The owner of a foreign vessel or any other person not being in either case any person to whom any of the descriptions specifications in sub-items (1) to (3) of item (i) of sub-clause (II) of clause (e) of section 2 any maritime zone of India, may make an application to the Central Government for the grant of a licence.
[...]
5. (1) Every Indian citizen and every person to whom any of the descriptions specified in sub-item (2) or (3) of item (i) of sub-clause (II) of clause (e) of section (2) applies, who intends to use any foreign vessel for fishing within any maritime zone of India, may make an application to the Central Government for a permit to use such vessel for such purpose.[...]" (THE MARITIME ZONES OF INDIA (REGULATION OF FISHING BY FOREIGN VESSELS) ACT, 1981)
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"POLICY INTERVENTIONS
9. MARINE SECTOR
Fisheries Management [...]
(x) Foreign fishing vessels will not be allowed to fish or undertake fishing related activities in India’s sovereign waters. [...]" (NATIONAL FISHERIES POLICY, 2020)
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"All Indian entrepreneurs, who intend to do fishing in the Exclusive Economic Zone of India [...] will have to otain a Letter of Permission (LOP) from the Department of Animal Husbandry, Dairying and Fisheries, Ministry of Agriculture, Goverment of India.
1. The LOP will be issued to all eligible Indian entrepreneurs who satisfy the following conditions: [...]
i) Grant of LOPs would be considered only to resource specific deep-sea fishing vessels [...]
iii) the mode of acquisition can be: a) outright purchase; b) deferred payment; and c) Joint Venture with not less than 51% Indian equity [...]" (Public Notice No 21002/12/2011-Fy(Ind), Government of India/Ministry of Agriculture, 28 November 2014)
--------------------------------
"DEFINITIONS [...]
4. Operator: Any Indian citizen, Indian entrepreneur; Partnership Firm; Private Ltd. Company; Public Ltd. Company; Joint Venture Company (with at least 51% Indian equity), Corporation and registered Cooperative Society.
[...]
Guidelines:
1. A Letter of Permission (LOP) in writting is required from the Department of Animal Husbandry, Dairying and Fisheries for operating any fishing vessel in Indian EEZ. [...]" (Guidelines for operation of Deep Sea Fishing Vessels in the Indian Exclusive Economic Zone (EEZ), 12th November, 2014)
Government of India/Ministry of Commerce and Industry (2020), Consolidated FDI Policy (Effective from October 15, 2020)
THE MARITIME ZONES OF INDIA (REGULATION OF FISHING BY FOREIGN VESSELS) ACT, 1981
NATIONAL FISHERIES POLICY, 2020
Public Notice No 21002/12/2011-Fy(Ind), Government of India/Ministry of Agriculture, 28 November 2014
Guidelines for operation of Deep Sea Fishing Vessels in the Indian Exclusive Economic Zone (EEZ), 12th November, 2014
[<a href="https://dpiit.gov.in/sites/default/files/FDI-PolicyCircular-2020-29October2020_0.pdf">Policy</a>],[<a href="https://dof.gov.in/actsandrules/maritime-zones-india-regulation-fishing-foreign-vessels-act-1981#">Act</a>],[<a href="https://faolex.fao.org/docs/pdf/ind201321.pdf">Policy</a>],[<a href="https://fisheries.maharashtra.gov.in/sites/default/files/Government_of_India_Public_Notice_Dt_28-11-2014_Regarding_Fishing_In_Exclusive_Economic_Zone_of_India_And_Obtaining_LOP_of_GOI.pdf">Notice</a>],[<a href="https://fisheries.maharashtra.gov.in/sites/default/files/GOI_Order_Dt_12-11-2014_And_Guidelines_of_Government_of_India_For_Fishing_Operation_In_Indian_Exclusive_Economic_Zone_2014.pdf">Guidelines</a>]